<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt src="https://files.passeidireto.com/ea027e35-c51f-4c05-a101-53e2a349c319/bg1.png" alt="Pré-visualização de imagem de arquivo"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls68 ws0">UFPR – Departamen<span class="blank _0"></span>to de F<span class="blank _1"></span>´<span class="blank _2"></span>ısica</div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 ls68 ws0">CF368/Eletromagnetismo I – Pro<span class="blank _0"></span>v<span class="blank _3"></span>a <span class="ff2 ls0">P</span><span class="ff3 fs1 v1">1</span></div><div class="t m0 x3 h2 y3 ff1 fs0 fc0 sc0 ls68 ws0">Prof.<span class="blank _4"> </span>Alexandre D. Rib<span class="blank _5"> </span>eiro (04/09/2019)</div><div class="t m0 x0 h2 y4 ff4 fs0 fc0 sc0 ls68 ws1">Observ<span class="blank _3"></span>a¸<span class="blank _2"></span>c˜<span class="blank _6"></span>oes: <span class="ff1 ws2">i) </span><span class="ws3">Indique de forma organizada o racio<span class="blank _5"> </span>c<span class="blank _1"></span>´<span class="blank _7"></span>ınio</span></div><div class="t m0 x0 h2 y5 ff4 fs0 fc0 sc0 ls68 ws4">e to<span class="blank _5"> </span>dos os c´<span class="blank _6"></span>alculos usados na solu¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao;<span class="blank _4"> </span><span class="ff1 ws5">ii) </span>F´<span class="blank _8"></span>orm<span class="blank _0"></span>ulas n˜<span class="blank _8"></span>ao-</div><div class="t m0 x0 h2 y6 ff4 fs0 fc0 sc0 ls68 ws6">p<span class="blank _5"> </span>ertencen<span class="blank _0"></span>tes ao form<span class="blank _0"></span>ul´<span class="blank _8"></span>ario da prov<span class="blank _3"></span>a,<span class="blank _9"> </span>quando utilizadas,</div><div class="t m0 x0 h2 y7 ff4 fs0 fc0 sc0 ls68 ws7">dev<span class="blank _0"></span>em ser deduzidas.</div><div class="t m0 x0 h2 y8 ff1 fs0 fc0 sc0 ls68 ws8">Problema 1:<span class="blank _a"> </span><span class="ff4 ws9">Uma carga p<span class="blank _5"> </span>on<span class="blank _0"></span>tual <span class="ff2 ls1">q</span>´<span class="blank _6"></span>e mantida sobre o eixo</span></div><div class="t m0 x0 h2 y9 ff2 fs0 fc0 sc0 ls2">z<span class="ff4 ls68 wsa">e a uma distˆ<span class="blank _8"></span>ancia <span class="ff2 ls3">d</span>acima de um plano condutor infinito</span></div><div class="t m0 x0 h2 ya ff4 fs0 fc0 sc0 ls68 ws7">e aterrado (figura abaixo).</div><div class="t m0 x4 h3 yb ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x5 h3 yc ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x6 h3 yd ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x7 h3 ye ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x8 h3 yf ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x9 h3 y10 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xa h3 y11 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xb h3 y12 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xc h3 y13 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xd h3 y14 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xe h3 y15 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xf h3 y16 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x10 h3 y17 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x11 h3 y18 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x12 h3 y19 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x13 h3 y1a ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x4 h3 y1b ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x5 h3 y1c ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x6 h3 y1d ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x7 h3 y1e ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x8 h3 y1f ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x9 h3 y20 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xa h3 y21 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xb h3 y22 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xc h3 y23 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xd h3 y24 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xe h3 y11 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xf h3 y25 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x10 h3 y26 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x11 h3 yf ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x12 h3 y27 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x13 h3 y28 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xb h3 y29 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xc h3 y2a ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xd h3 y2b ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xe h3 y2c ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xf h3 y2d ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x10 h3 y2e ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x11 h3 y2f ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x12 h3 y30 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x14 h3 y31 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x15 h3 y32 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x16 h3 y33 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x17 h3 y34 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x18 h3 y35 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x19 h3 y36 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1a h3 y37 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1b h3 y38 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1c h3 y39 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1d h3 y3a ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1e h3 y3b ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1f h3 y3c ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x20 h3 y3d ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x21 h3 y3e ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x22 h3 y3f ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x23 h3 y40 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x24 h3 y41 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1c h3 y42 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1d h3 y43 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1e h3 y44 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1f h3 y45 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x20 h3 y46 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x21 h3 y47 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x22 h3 y48 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x25 h3 y49 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x24 h3 y4a ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x26 h3 y4b ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x27 h3 y4c ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x28 h3 y4d ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x29 h3 y4e ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x2a h3 y4f ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x2b h3 y50 ff5 fs0 fc0 sc0 ls4"><span class="ls68 v2">H</span></div><div class="t m0 xc h3 y51 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xd h3 y52 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xe h3 y53 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xf h3 y54 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x10 h3 y55 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x11 h3 y56 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x12 h3 y57 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2c h3 y58 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2d h3 y59 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2e h3 y5a ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2f h3 y5b ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x30 h3 y5c ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x31 h3 y5d ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x32 h3 y5e ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x33 h3 y5f ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x28 h3 y60 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x29 h3 y61 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2a h3 y62 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2b h3 y63 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2f h3 y64 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x30 h3 y65 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x31 h3 y66 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x32 h3 y67 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x27 h3 y68 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x28 h3 y69 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x29 h3 y6a ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2a h3 y6b ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x2b h3 y6c ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x34 h3 y6d ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x35 h3 y6e ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x36 h3 y6f ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x24 h3 y53 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1c h3 y70 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1d h3 y55 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1e h3 y56 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1f h3 y71 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x20 h3 y72 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x21 h3 y73 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x22 h3 y74 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x37 h3 y5b ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x38 h3 y5c ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1c h3 y5d ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1d h3 y5e ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x14 h3 y5f ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x15 h3 y75 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x16 h3 y76 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x17 h3 y77 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x39 h3 y63 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x37 h3 y64 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x38 h3 y78 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x3a h3 y66 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x3b h3 y67 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x14 h3 y79 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x15 h3 y7a ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x16 h3 y7b ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xf h4 y7c ff6 fs0 fc0 sc0 ls5">H<span class="ls68 wsb v3">H</span><span class="v4">H<span class="v3">H</span></span><span class="ls68 wsb v5">H</span><span class="v6">H<span class="v3">H</span></span><span class="ls68 wsb v7">H</span><span class="v8">H</span><span class="ls68 wsb v9">H<span class="blank _b"></span>j</span></div><div class="t m0 x25 h2 y7d ff2 fs0 fc0 sc0 ls68">y</div><div class="t m0 x7 h4 y25 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x8 h4 y26 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x9 h4 yf ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xa h4 y7e ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xb h4 y7f ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xc h4 y80 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xd h4 y81 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xe h4 y82 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xf h4 yb ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x10 h4 y1b ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x11 h4 y83 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x12 h4 y84 ff6 fs0 fc0 sc0 ls68 wsb"><span class="blank _b"></span>)</div><div class="t m0 x3c h2 y20 ff2 fs0 fc0 sc0 ls68">x</div><div class="t m0 x2a h4 y85 ff6 fs0 fc0 sc0 ls68">6</div><div class="t m0 xb h2 y86 ff2 fs0 fc0 sc0 ls68">z</div><div class="t m0 x2a h2 y87 ff7 fs0 fc0 sc0 ls6">t<span class="ff2 ls68">q</span></div><div class="t m0 x5 h2 ye ff2 fs0 fc0 sc0 ls7">V<span class="ff4 ls68 wsc">= 0</span></div><div class="t m0 x0 h2 y88 ff4 fs0 fc0 sc0 ls68 wsd">(a) Justificando to<span class="blank _5"> </span>dos os seus passos, atrav<span class="blank _3"></span>´<span class="blank _2"></span>es do m<span class="blank _0"></span>´<span class="blank _6"></span>eto<span class="blank _5"> </span>do das</div><div class="t m0 x0 h2 y89 ff4 fs0 fc0 sc0 ls68 wse">imagens, encontre uma express˜<span class="blank _8"></span>ao para o potencial el´<span class="blank _6"></span>etrico</div><div class="t m0 x0 h2 y8a ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span>z <span class="ff4 ws7">) na regi˜<span class="blank _8"></span>ao acima do<span class="blank _d"> </span>plano. (1,00)</span></span></div><div class="t m0 x0 h2 y8b ff4 fs0 fc0 sc0 ls68 ws11">(b) Uma distribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao sup<span class="blank _5"> </span>erficial de cargas <span class="ff2 ls9">σ</span><span class="wsf">(<span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws11">) est´<span class="blank _8"></span>a rela-</span></span></span></div><div class="t m0 x0 h2 y8c ff4 fs0 fc0 sc0 ls68 ws13">cionada ao p<span class="blank _5"> </span>otencial el<span class="blank _0"></span>´<span class="blank _6"></span>etrico <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws7">) atra<span class="blank _0"></span>v´<span class="blank _8"></span>es de</span></span></span></div><div class="t m0 xe h2 y8d ff2 fs0 fc0 sc0 lsa">σ<span class="ff4 lsb">=<span class="ff8 lsc">−</span></span><span class="lsd"><span class="ff3 fs1 ls68 v1">0</span></span></div><div class="t m0 x2c h2 y8e ff2 fs0 fc0 sc0 ls68 ws14">∂ V</div><div class="t m0 x2c h5 y8f ff2 fs0 fc0 sc0 ls68 ws14">∂ n<span class="blank _e"> </span><span class="va">,</span></div><div class="t m0 x0 h2 y90 ff4 fs0 fc0 sc0 ls68 ws15">em que <span class="ff2 lse">n</span><span class="ws16">´<span class="blank _6"></span>e a co<span class="blank _5"> </span>ordenada p<span class="blank _5"> </span>erp<span class="blank _5"> </span>endicular `<span class="blank _8"></span>a sup<span class="blank _5"> </span>erf<span class="blank _f"></span>´<span class="blank _7"></span>ıcie.<span class="blank _a"> </span>Mostre</span></div><div class="t m0 x0 h2 y91 ff4 fs0 fc0 sc0 ls68 ws17">que, para o nosso problema, a carga induzida no plano con-</div><div class="t m0 x0 h2 y92 ff4 fs0 fc0 sc0 ls68 ws18">dutor<span class="blank _10"> </span>´<span class="blank _6"></span>e<span class="blank _d"> </span>caracterizada<span class="blank _10"> </span>p or</div><div class="t m0 x2 h6 y93 ff2 fs0 fc0 sc0 lsf">σ<span class="ff4 ls68 wsf">(</span><span class="ls68 ws19">x,<span class="blank _c"> </span>y <span class="ff4 wsc">) =<span class="blank _11"> </span><span class="ff8 lsc va">−</span></span><span class="ws10 va">q d</span></span></div><div class="t m0 x3d h7 y94 ff4 fs0 fc0 sc0 ls68 wsf">2<span class="ff2 ls10">π</span>(<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls14">y<span class="ff3 fs1 ls12 vb">2</span></span>+</span><span class="ff2 ws1a">d<span class="ff3 fs1 ls15 vb">2</span></span><span class="ls16">)</span><span class="ff3 fs1 ws1b vb">3<span class="ff9 ls17">/<span class="ff3 ls18">2</span></span></span><span class="ff2 ls19 va">.</span><span class="va">(1<span class="ff2 ls1a">,</span>00)</span></div><div class="t m0 x0 h2 y95 ff4 fs0 fc0 sc0 ls68 ws1c">(c) Mostre que a con<span class="blank _0"></span>tribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao desta distribui¸<span class="blank _12"></span>c˜<span class="blank _8"></span>ao <span class="ff2 ls9">σ</span><span class="ws1d">, somada</span></div><div class="t m0 x0 h2 y96 ff4 fs0 fc0 sc0 ls68 ws1e">`<span class="blank _8"></span>a contribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao da carga p<span class="blank _5"> </span>on<span class="blank _0"></span>tual, pro<span class="blank _5"> </span>duz o mesmo p<span class="blank _5"> </span>otencial</div><div class="t m0 x0 h2 y97 ff4 fs0 fc0 sc0 ls68 ws7">el<span class="blank _0"></span>´<span class="blank _6"></span>etrico encontrado em (a).<span class="blank _a"> </span>Para isso, utilize</div><div class="t m0 x3e h6 y98 ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 wsc">) =<span class="blank _13"> </span><span class="va">1</span></span></span></span></div><div class="t m0 x2f h8 y99 ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ws10">π <span class="ff3 fs1 ls1b v1">0</span><span class="ffa ws1f vc">Z</span><span class="ff3 fs1 vd">tudo</span></span></div><div class="t m0 x27 h9 y9a ff2 fs0 fc0 sc0 ls68 ws20">σ da<span class="ffb fs1 ve">0</span></div><div class="t m0 x3a h5 y99 ff8 fs0 fc0 sc0 ls1c">R<span class="ff2 ls68 va">.</span></div><div class="t m0 x0 h2 y9b ff1 fs0 fc0 sc0 ls68 ws21">Mostre isso ap<span class="blank _5"> </span>enas para p<span class="blank _5"> </span>on<span class="blank _0"></span>tos sobre o eixo <span class="ff2 ls1d">z</span><span class="ls1e">!</span><span class="ff4">(2,00)</span></div><div class="t m0 x0 h2 y9c ff4 fs0 fc0 sc0 ls68 ws13">Dev<span class="blank _0"></span>e ser<span class="blank _d"> </span>´<span class="blank _8"></span>util a express˜<span class="blank _8"></span>ao</div><div class="t m0 x3f h2 y9d ff2 fs0 fc0 sc0 ls68">d</div><div class="t m0 x40 ha y9e ff2 fs0 fc0 sc0 ls68 ws22">dx <span class="ffa ls1f vf"></span><span class="ff4 wsf v10">(</span><span class="ls11 v10">x</span><span class="ff3 fs1 ls12 v11">2</span><span class="ff4 ls13 v10">+</span><span class="ls20 v10">b</span><span class="ff3 fs1 ls15 v11">2</span><span class="ff4 wsf v10">)</span><span class="ff3 fs1 ls21 v11">1<span class="ff9 ls68 ws23">/<span class="ff3">2</span></span></span></div><div class="t m0 x41 hb y9f ff4 fs0 fc0 sc0 ls68 wsf">(<span class="ff2 ws1a">a<span class="ff3 fs1 ls12 vb">2</span><span class="ff8 ls13">−</span><span class="ls20">b<span class="ff3 fs1 ls15 vb">2</span></span></span>)(<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+</span><span class="ff2 ws1a">a<span class="ff3 fs1 ls15 vb">2</span></span>)<span class="ff3 fs1 ls21 vb">1<span class="ff9 ls17">/<span class="ff3 ls22">2</span></span></span><span class="ffa ls23 vf"></span><span class="ls24 va">=</span><span class="ff2 v10">x</span></div><div class="t m0 x1e h7 y9f ff4 fs0 fc0 sc0 ls16">(<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls68 ws1a">a<span class="ff3 fs1 ls15 vb">2</span></span></span>)<span class="ff3 fs1 ls68 ws1b vb">3<span class="ff9 ls17">/<span class="ff3 ls15">2</span></span></span><span class="ls68 wsf">(<span class="ff2 ls11">x<span class="ff3 fs1 ls25 vb">2</span></span><span class="ls26">+<span class="ff2 ls20">b<span class="ff3 fs1 ls15 vb">2</span></span></span></span>)<span class="ff3 fs1 ls68 ws1b vb">1<span class="ff9 ls17">/<span class="ff3 ls18">2</span></span></span><span class="ff2 ls68 va">.</span></div><div class="t m0 x0 h2 ya0 ff1 fs0 fc0 sc0 ls68 ws24">Resolu¸<span class="blank _8"></span>c˜<span class="blank _14"></span>ao do Problema 1:<span class="blank _15"> </span><span class="ff4 ws25">(a) Precisamos resolv<span class="blank _0"></span>er</span></div><div class="t m0 x0 h2 ya1 ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span>z <span class="ff4 ws26">) na regi˜<span class="blank _8"></span>ao <span class="ff2 ws27">z<span class="blank _4"> </span>> </span><span class="ws28">0,<span class="blank _4"> </span>com <span class="ff2 ls27">x</span><span class="ls28">e<span class="ff2 ls29">y</span></span><span class="ws29">quaisquer.<span class="blank _16"> </span>O<span class="blank _17"> </span>p o-</span></span></span></span></div><div class="t m0 x0 h2 ya2 ff4 fs0 fc0 sc0 ls68 ws7">tencial<span class="blank _10"> </span>´<span class="blank _6"></span>e determinado p<span class="blank _5"> </span>ela distribui¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao de cargas</div><div class="t m0 xf hc ya3 ff2 fs0 fc0 sc0 ls2a">ρ<span class="ff4 ls68 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws2a">) = </span><span class="ws2b">q<span class="blank _18"> </span>δ <span class="ff3 fs1 ws2c v12">(3) </span><span class="ff4 wsf">(<span class="blank _0"></span><span class="ff2 ws2d">~<span class="blank _6"></span>r <span class="ff8 ls13">−</span><span class="ls2b">d</span><span class="ff4 wsf">ˆ<span class="blank _8"></span><span class="ff2 ls1d">z<span class="ff4 ls2c">)</span><span class="ls68">,</span></span></span></span></span></span></span></span></div><div class="t m0 x0 h2 ya4 ff4 fs0 fc0 sc0 ls68 ws7">e p<span class="blank _5"> </span>elas condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes de contorno</div><div class="t m0 x42 h2 ya5 ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span><span class="ff4 ws2e">0) = 0<span class="blank _19"> </span>e<span class="blank _1a"> </span>lim</span></span></div><div class="t m0 x9 hd ya6 ff9 fs1 fc0 sc0 ls2d">r<span class="ffb ls68 ws2f">→<span class="ff3 ls2e">0<span class="ff2 fs0 ls2f v13">V<span class="ff4 ls16">(<span class="ff2 ls68 ws30">x, y<span class="blank _5"> </span>, z<span class="blank _5"> </span></span><span class="ls30">)<span class="ff8 ls31">→</span><span class="ls68 wsf">0<span class="ff2">,</span></span></span></span></span></span></span></div><div class="t m0 x43 he y1 ff4 fs0 fc0 sc0 ls68 ws31">sendo <span class="ff2 ls32">r</span><span class="ls33">=<span class="ffa ls5 v14">p</span><span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls14">y<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls26">+<span class="ff2 ls34">z<span class="ff3 fs1 ls15 vb">2</span></span></span></span></span><span class="ws32">.<span class="blank _9"> </span>Al<span class="blank _3"></span>´<span class="blank _2"></span>em disso, teoremas de unici-</span></div><div class="t m0 x43 h2 y2 ff4 fs0 fc0 sc0 ls68 ws33">dade nos garan<span class="blank _0"></span>tem que qualquer express˜<span class="blank _8"></span>ao para <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span>z<span class="blank _1b"> </span></span>)</span></div><div class="t m0 x43 h2 y3 ff4 fs0 fc0 sc0 ls68 ws34">que resp<span class="blank _5"> </span>eite os v<span class="blank _1"></span>´<span class="blank _7"></span>ınculos acima, dentro da regi˜<span class="blank _8"></span>ao estudada</div><div class="t m0 x43 h2 ya7 ff4 fs0 fc0 sc0 ls68 wsf">(<span class="ff2 ws35">z<span class="blank _9"> </span>> </span><span class="ws36">0 neste caso),<span class="blank _4"> </span>´<span class="blank _2"></span>e a ´<span class="blank _8"></span>unica solu¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao<span class="blank _4"> </span>do problema.<span class="blank _15"> </span>O</span></div><div class="t m0 x43 h2 ya8 ff4 fs0 fc0 sc0 ls68 ws37">m<span class="blank _0"></span>´<span class="blank _6"></span>eto<span class="blank _5"> </span>do das imagens faz uso deste<span class="blank _10"> </span>´<span class="blank _14"></span>ultimo p<span class="blank _5"> </span>onto, para elab<span class="blank _5"> </span>o-</div><div class="t m0 x43 h2 ya9 ff4 fs0 fc0 sc0 ls68 ws38">rar um problema equiv<span class="blank _3"></span>alente que respeite aquelas condi¸<span class="blank _2"></span>c˜<span class="blank _6"></span>oes</div><div class="t m0 x43 h2 yaa ff4 fs0 fc0 sc0 ls68 ws7">e que, p<span class="blank _5"> </span>ortan<span class="blank _0"></span>to, pro<span class="blank _5"> </span>duza um potencial el´<span class="blank _6"></span>etrico idˆ<span class="blank _6"></span>en<span class="blank _0"></span>tico.</div><div class="t m0 x44 h2 yab ff4 fs0 fc0 sc0 ls68 ws39">Problema equiv<span class="blank _3"></span>alente:<span class="blank _1c"> </span>Considere uma distribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao de</div><div class="t m0 x43 h2 yac ff4 fs0 fc0 sc0 ls68 ws29">cargas<span class="blank _1d"> </span>dada<span class="blank _1d"> </span>p or</div><div class="t m0 x45 hf yad ff2 fs0 fc0 sc0 ls68 ws1a">ρ<span class="ff9 fs1 ws3a v1">eq </span><span class="ff4 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws2a">) = </span><span class="ws2b">q<span class="blank _18"> </span>δ <span class="ff3 fs1 ws2c v12">(3) </span><span class="ff4 wsf">(<span class="blank _0"></span><span class="ff2 ws2d">~<span class="blank _6"></span>r <span class="ff8 ls26">−</span><span class="ls35">d</span><span class="ff4 wsf">ˆ<span class="blank _8"></span><span class="ff2 ls1d">z<span class="ff4 ls36">)<span class="ff8 ls13">−</span></span><span class="ls68 ws2b">q<span class="blank _1d"> </span>δ <span class="ff3 fs1 ws2c v12">(3) </span><span class="ff4 wsf">(</span><span class="ws2d">~<span class="blank _6"></span>r <span class="ff4 ls26">+</span><span class="ls35">d</span><span class="ff4 wsf">ˆ<span class="blank _14"></span><span class="ff2 ls1d">z<span class="ff4 ls2c">)</span><span class="ls68">.</span></span></span></span></span></span></span></span></span></span></span></span></div><div class="t m0 x43 h2 yae ff4 fs0 fc0 sc0 ls68 ws3b">Em<span class="blank _0"></span>b<span class="blank _5"> </span>ora seja eviden<span class="blank _0"></span>te que <span class="ff2 ls2a">ρ</span><span class="ff9 fs1 ws3a v1">eq </span><span class="wsf">(<span class="blank _0"></span><span class="ff2 ws3c">~<span class="blank _6"></span>r <span class="ff4 ls37">)</span><span class="ff8 wsb">6<span class="ff4 lsb">=</span></span><span class="ls2a">ρ</span><span class="ff4 wsf">(</span><span class="ws12">~<span class="blank _6"></span>r <span class="ff4 ws3b">) no espa¸<span class="blank _2"></span>co to<span class="blank _5"> </span>do, se</span></span></span></span></div><div class="t m0 x43 h2 yaf ff4 fs0 fc0 sc0 ls68 ws7">nos limitarmos `<span class="blank _8"></span>a regi˜<span class="blank _6"></span>ao de interesse <span class="ff2 ws3d">z > </span>0, verifica-se que</div><div class="t m0 x46 h2 yb0 ff2 fs0 fc0 sc0 ls68 ws1a">ρ<span class="ff9 fs1 ws3a v1">eq </span><span class="ff4 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws2a">) = </span><span class="ls2a">ρ</span><span class="ff4 wsf">(</span><span class="ws3c">~<span class="blank _6"></span>r <span class="ff4 ws3e">) (</span><span class="ws3f">~<span class="blank _6"></span>r <span class="ff4 ws40">tais que </span><span class="ws41">z<span class="blank _10"> </span>> <span class="ff4 wsf">0)</span>.</span></span></span></span></span></div><div class="t m0 x43 h2 yb1 ff4 fs0 fc0 sc0 ls68 ws42">Al<span class="blank _0"></span>´<span class="blank _6"></span>em disso,<span class="blank _9"> </span>por conta da simetria,<span class="blank _4"> </span>p<span class="blank _5"> </span>ontos equidistan<span class="blank _3"></span>tes</div><div class="t m0 x43 h2 yb2 ff4 fs0 fc0 sc0 ls68 ws43">das cargas p<span class="blank _5"> </span>ossuem potencial el´<span class="blank _6"></span>etrico nulo.<span class="blank _1c"> </span>Isto implica</div><div class="t m0 x43 h2 yb3 ff4 fs0 fc0 sc0 ls68 ws44">em <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span></span><span class="ws45">0) =<span class="blank _10"> </span>0.<span class="blank _18"> </span>T<span class="blank _3"></span>am<span class="blank _0"></span>b´<span class="blank _8"></span>em,<span class="blank _10"> </span>para pontos m<span class="blank _3"></span>uito distantes, o</span></span></div><div class="t m0 x43 h2 yb4 ff4 fs0 fc0 sc0 ls68 ws1e">p<span class="blank _5"> </span>otencial devido `<span class="blank _8"></span>as duas cargas tende a ser nulo (<span class="ff2 ls7">V<span class="ff8 lsb">∼</span></span><span class="ls38">1</span><span class="ff2 ws46">/r</span>).</div><div class="t m0 x43 h2 yb5 ff4 fs0 fc0 sc0 ls68 ws47">Logo, to<span class="blank _5"> </span>das as restri¸<span class="blank _2"></span>c˜<span class="blank _6"></span>oes apresentadas no problema original</div><div class="t m0 x43 h2 yb6 ff4 fs0 fc0 sc0 ls68 ws9">tam<span class="blank _0"></span>b´<span class="blank _8"></span>em devem ser respeitadas neste problema equiv<span class="blank _0"></span>alen<span class="blank _0"></span>te.</div><div class="t m0 x43 h2 yb7 ff4 fs0 fc0 sc0 ls68 ws48">Seus p<span class="blank _5"> </span>otenciais, p<span class="blank _5"> </span>ortan<span class="blank _0"></span>to, s˜<span class="blank _6"></span>ao equiv<span class="blank _3"></span>alentes na regi˜<span class="blank _8"></span>ao <span class="ff2 ws41">z<span class="blank _10"> </span>> </span>0.</div><div class="t m0 x44 h2 yb8 ff4 fs0 fc0 sc0 ls68 ws49">O p<span class="blank _5"> </span>otencial do sistema equiv<span class="blank _3"></span>alente consiste da con-</div><div class="t m0 x43 h2 yb9 ff4 fs0 fc0 sc0 ls68 ws7">tribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao das duas cargas:</div><div class="t m0 x47 h10 yba ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls16">(</span><span class="ls68 ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span>z <span class="ff4 wsc">) =<span class="blank _13"> </span><span class="va">1</span></span></span></div><div class="t m0 x48 h11 ybb ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ws10">π <span class="ff3 fs1 ls39 v1">0</span><span class="ffa ls3a vf"></span></span><span class="lsc v10">+</span><span class="ff2 v10">q</span></div><div class="t m0 x49 h2 ybb ff8 fs0 fc0 sc0 ls3b">R<span class="ff3 fs1 ls68 v1">+</span></div><div class="t m0 x4a h6 ybc ff4 fs0 fc0 sc0 ls3c">+<span class="ff8 lsc va">−<span class="ff2 ls68">q</span></span></div><div class="t m0 x4b h11 ybb ff8 fs0 fc0 sc0 ls3b">R<span class="ffb fs1 ls3d v1">−</span><span class="ffa ls3e vf"></span><span class="ff2 ls68 va">,</span></div><div class="t m0 x43 h2 ybd ff4 fs0 fc0 sc0 ls68 ws7">em que <span class="ff8 ls3b">R<span class="ffb fs1 ls3f v1">±</span></span>´<span class="blank _6"></span>e a distˆ<span class="blank _6"></span>ancia da carga <span class="ff8 lsc">±<span class="ff2 ls40">q</span></span><span class="ws4a">at´<span class="blank _8"></span>e <span class="ff2 ws4b">~<span class="blank _2"></span>r <span class="ff4 wsc">= (</span><span class="ws10">x,<span class="blank _c"> </span>y ,<span class="blank _c"> </span>z <span class="ff4">),</span></span></span></span></div><div class="t m0 x4c h12 ybe ff8 fs0 fc0 sc0 ls3b">R<span class="ffb fs1 ls41 v1">±</span><span class="ff4 lsb">=</span><span class="ls68 wsb">|<span class="ff4 ls16">(</span><span class="ff2 ws30">x, y<span class="blank _5"> </span>, z<span class="blank _1e"> </span></span><span class="ls13">∓</span><span class="ff2 ws1a">d<span class="ff4 ls16">)</span></span><span class="ls42">|<span class="ff4 lsb">=<span class="ffa ls5 v15">q</span><span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls14">y<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls68 ws4c">+ (<span class="ff2 ls43">z</span></span><span class="ff8">∓</span></span></span></span><span class="ff2 ws1a">d<span class="ff4 ls16">)<span class="ff3 fs1 ls15 v16">2</span></span>.</span></span></div><div class="t m0 x43 h2 ybf ff4 fs0 fc0 sc0 ls68 ws4d">(b) P<span class="blank _0"></span>ara este caso,<span class="blank _1e"> </span><span class="ff2 ls44">n</span><span class="ws16">´<span class="blank _6"></span>e a pr´<span class="blank _8"></span>opria co<span class="blank _5"> </span>ordenada <span class="ff2 ls1d">z</span><span class="ws18">,<span class="blank _1e"> </span>e<span class="blank _e"> </span>a<span class="blank _e"> </span>sup erf<span class="blank _f"></span>´<span class="blank _7"></span>ıcie</span></span></div><div class="t m0 x43 h2 yc0 ff4 fs0 fc0 sc0 ls68 ws4e">encon<span class="blank _0"></span>tra-se em <span class="ff2 ls45">z</span><span class="wsc">= 0.<span class="blank _17"> </span>Assim,</span></div><div class="t m0 x43 h2 yc1 ff2 fs0 fc0 sc0 ls46">σ<span class="ff4 ls47">=<span class="ff8 ls68 wsb">−</span></span><span class="lsd"><span class="ff3 fs1 ls68 v1">0</span></span></div><div class="t m0 x4d h2 yc2 ff2 fs0 fc0 sc0 ls68 ws14">∂ V</div><div class="t m0 x4e h13 yc3 ff2 fs0 fc0 sc0 ls68 ws14">∂ z<span class="blank _10"> </span><span class="ffa v17"></span></div><div class="t m0 x4f h14 yc4 ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x4f h14 yc5 ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x4f h14 yc6 ffa fs0 fc0 sc0 ls48"><span class="ff9 fs1 ls49 v18">z<span class="ff3 ls68">=0</span></span></div><div class="t m0 x50 h2 yc1 ff4 fs0 fc0 sc0 lsb">=<span class="ff8 ls68 wsb">−<span class="ff2 lsd"></span><span class="ff3 fs1 v1">0</span></span></div><div class="t m0 x51 h2 yc2 ff4 fs0 fc0 sc0 ls68">1</div><div class="t m0 x52 h2 yc3 ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ws10">π <span class="ff3 fs1 v1">0</span></span></div><div class="t m0 x53 h2 yc2 ff2 fs0 fc0 sc0 ls68">∂</div><div class="t m0 x54 h11 yc3 ff2 fs0 fc0 sc0 ls68 ws14">∂ z<span class="blank _1d"> </span><span class="ffa ls4a vf"></span><span class="v10">q</span></div><div class="t m0 x55 h2 yc3 ff8 fs0 fc0 sc0 ls68 wsb">R<span class="ff3 fs1 v1">+</span></div><div class="t m0 x56 h6 yc1 ff8 fs0 fc0 sc0 ls4b">−<span class="ff2 ls68 va">q</span></div><div class="t m0 x57 h13 yc3 ff8 fs0 fc0 sc0 ls68 wsb">R<span class="ffb fs1 ls3d v1">−</span><span class="ffa ws1f vf"><span class="v19"></span></span></div><div class="t m0 x58 h14 yc4 ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x58 h14 yc5 ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x58 h14 yc6 ffa fs0 fc0 sc0 ls48"><span class="ff9 fs1 ls4c v18">z<span class="ff3 ls68">=0</span></span></div><div class="t m0 x59 h6 yc7 ff4 fs0 fc0 sc0 ls47">=<span class="ff8 ls4d">−<span class="ff2 ls68 va">q</span></span></div><div class="t m0 x5a h15 yc8 ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ls4e">π</span><span class="ffa ws1f vf"></span><span class="ff8 ls4f va">−</span><span class="v10">1</span></div><div class="t m0 x5b h2 yc8 ff4 fs0 fc0 sc0 ls68">2</div><div class="t m0 x5c h2 yc9 ff4 fs0 fc0 sc0 ls68 ws4f">2 (<span class="ff2 ls43">z<span class="ff8 ls13">−</span><span class="ls68 ws1a">d</span></span>)</div><div class="t m0 x50 h16 yc8 ff8 fs0 fc0 sc0 ls68 wsb">R<span class="ff3 fs1 ve">3</span></div><div class="t m0 x5d h17 yca ff3 fs1 fc0 sc0 ls68">+</div><div class="t m0 x5e h6 yc7 ff4 fs0 fc0 sc0 ls50">+<span class="ls68 va">1</span></div><div class="t m0 x5f h2 yc8 ff4 fs0 fc0 sc0 ls68">2</div><div class="t m0 x60 h2 yc9 ff4 fs0 fc0 sc0 ls68 ws4f">2 (<span class="ff2 ls51">z</span><span class="ls26">+<span class="ff2 ls52">d</span></span>)</div><div class="t m0 x61 h16 yc8 ff8 fs0 fc0 sc0 ls68 wsb">R<span class="ff3 fs1 ve">3</span></div><div class="t m0 x62 h18 yca ffb fs1 fc0 sc0 ls53">−<span class="ffa fs0 ls54 v1a"><span class="ls68 v19"></span></span></div><div class="t m0 x56 h14 ycb ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x56 h14 ycc ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x56 h14 ycd ffa fs0 fc0 sc0 ls68 ws1f"><span class="ff9 fs1 ls4c v1b">z<span class="ff3 ls68">=0</span></span></div><div class="t m0 x59 h6 yce ff4 fs0 fc0 sc0 ls55">=<span class="ff2 ls68 va">q</span></div><div class="t m0 x63 h19 ycf ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ls56">π<span class="ffa ls57 v1c">"</span></span><span class="ws50 v10">(0 <span class="ff8 ls13">−<span class="ff2 ls68 ws1a">d<span class="ff4">)</span></span></span></span></div><div class="t m0 x4e h1a yd0 ff4 fs0 fc0 sc0 ls68 wsf">[<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls14">y<span class="ff3 fs1 ls12 vb">2</span></span></span><span class="ws4c">+ (<span class="ff8 lsc">−</span><span class="ff2 ws1a">d</span><span class="ls16">)<span class="ff3 fs1 ls15 v16">2</span></span></span>]<span class="ff3 fs1 ls21 vb">3<span class="ff9 ls17">/<span class="ff3 ls58">2</span></span></span><span class="ff8 ls59 v1d">−</span><span class="ws4c v1e">(0 + <span class="ff2 ls52">d</span>)</span></div><div class="t m0 x62 h1b yd0 ff4 fs0 fc0 sc0 ls68 wsf">[<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls14">y<span class="ff3 fs1 ls12 vb">2</span></span></span><span class="ws4c">+ (+<span class="ff2 ws1a">d</span></span>)<span class="ff3 fs1 ls5a v16">2</span>]<span class="ff3 fs1 ws1b vb">3<span class="ff9 ls17">/<span class="ff3 ls18">2</span></span></span><span class="ffa v1f">#</span></div><div class="t m0 x59 h10 yd1 ff4 fs0 fc0 sc0 ls5b">=<span class="ff8 lsc va">−<span class="ff2 ls68 ws10">q d</span></span></div><div class="t m0 x63 h1c yd2 ff4 fs0 fc0 sc0 ls68 wsf">2<span class="ff2 ls10">π</span>(<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls14">y<span class="ff3 fs1 ls12 vb">2</span></span>+</span><span class="ff2 ws1a">d<span class="ff3 fs1 ls5a vb">2</span></span>)<span class="ff3 fs1 ws1b vb">3<span class="ff9 ls17">/<span class="ff3 ls18">2</span></span></span><span class="ff2 va">.</span></div><div class="t m0 x43 h2 yd3 ff4 fs0 fc0 sc0 ls68 ws7">(c) Calculamos primeiro a con<span class="blank _0"></span>tribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao do plano:</div><div class="t m0 x5a h6 yd4 ff2 fs0 fc0 sc0 ls68 ws1a">V<span class="ff3 fs1 ws51 v1">plano </span><span class="ff4 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 wsc">) =<span class="blank _13"> </span><span class="va">1</span></span></span></span></div><div class="t m0 x64 h1d yd5 ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ws10">π <span class="ff3 fs1 ls39 v1">0</span><span class="ffa ws1f vc">Z</span><span class="ff3 fs1 ws52 vd">todo<span class="blank _1e"> </span>plano</span></span></div><div class="t m0 x65 h9 yd6 ff2 fs0 fc0 sc0 ls68 ws20">σ da<span class="ffb fs1 ve">0</span></div><div class="t m0 x4b h5 yd5 ff8 fs0 fc0 sc0 ls1c">R<span class="ff2 ls68 va">.</span></div><div class="t m0 x43 h2 yd7 ff4 fs0 fc0 sc0 ls68 ws53">Aqui dev<span class="blank _0"></span>emos substituir a express˜<span class="blank _8"></span>ao obtida anteriormen<span class="blank _0"></span>te:</div><div class="t m0 x66 h6 yd8 ff2 fs0 fc0 sc0 lsa">σ<span class="ff4 ls5c">=<span class="ff8 lsc va">−</span></span><span class="ls68 ws10 va">q d</span></div><div class="t m0 x5a h1e yd9 ff4 fs0 fc0 sc0 ls68 wsf">2<span class="ff2 ls5d">π</span><span class="ls16">(<span class="ff2 ls11">x<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls5e">y<span class="ff3 fs1 ls25 vb">2</span></span><span class="ls26">+<span class="ff2 ls52">d<span class="ff3 fs1 ls15 vb">2</span></span></span></span></span>)<span class="ff3 fs1 ls21 vb">3<span class="ff9 ls17">/<span class="ff3 ls5f">2</span></span></span><span class="ls60 va">=</span><span class="ff8 lsc v10">−</span><span class="ff2 ws10 v10">q d</span></div><div class="t m0 x53 h1c yd9 ff4 fs0 fc0 sc0 ls38">2<span class="ff2 ls5d">π</span><span class="ls16">(<span class="ff2 ls68 ws1a">ρ<span class="ff3 fs1 ls25 vb">2</span></span><span class="ls26">+<span class="ff2 ls52">d<span class="ff3 fs1 ls15 vb">2</span></span><span class="ls68 wsf">)<span class="ff3 fs1 ls21 vb">3<span class="ff9 ls17">/<span class="ff3 ls22">2</span></span></span><span class="ff2 va">,</span></span></span></span></div><div class="t m0 x43 h2 yda ff4 fs0 fc0 sc0 ls68 ws54">em que <span class="ff2 ls61">ρ</span>´<span class="blank _6"></span>e o raio das co<span class="blank _5"> </span>ordenadas p<span class="blank _5"> </span>olares no plano,<span class="blank _4"> </span>d<span class="blank _0"></span>e</div><div class="t m0 x43 h1f ydb ff4 fs0 fc0 sc0 ls68 ws55">forma que <span class="ff2 ls2a">ρ<span class="ff3 fs1 ls62 ve">2</span></span><span class="ls63">=</span><span class="ff2 ws1a">x<span class="ff3 fs1 ls64 ve">2</span></span><span class="ls65">+<span class="ff2 ls14">y<span class="ff3 fs1 ls15 ve">2</span></span></span><span class="ws56">.<span class="blank _1f"> </span>Realizando a in<span class="blank _0"></span>tegra¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao em co-</span></div><div class="t m0 x43 h9 ydc ff4 fs0 fc0 sc0 ls68 ws57">ordenadas p<span class="blank _5"> </span>olares, temos que <span class="ff2 ws1a">da<span class="ffb fs1 ls66 ve">0</span></span><span class="ls67">=</span><span class="ff2 ws58">ρ dρ dθ<span class="blank _5"> </span></span><span class="ws59">. Finalmen<span class="blank _0"></span>te,</span></div></div><div class="pi" data-data="{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}"></div></div> <div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w2 h1" alt src="https://files.passeidireto.com/ea027e35-c51f-4c05-a101-53e2a349c319/bg2.png" alt="Pré-visualização de imagem de arquivo"><div class="t m0 x0 h2 y1 ff8 fs0 fc0 sc0 ls69">R<span class="ff4 ls68 ws13">´<span class="blank _6"></span>e a distˆ<span class="blank _6"></span>ancia de um p<span class="blank _5"> </span>onto (<span class="ff2 ws19">x,<span class="blank _c"> </span>y</span>) do plano at´<span class="blank _6"></span>e o p<span class="blank _5"> </span>on<span class="blank _0"></span>to <span class="ff2">z</span></span></div><div class="t m0 x0 h2 y2 ff4 fs0 fc0 sc0 ls68 ws2e">onde pretende-se calcular o p<span class="blank _5"> </span>otencial, sobre o eixo <span class="ff2 ls1d">z</span><span class="ws5b">. Logo,</span></div><div class="t m0 x0 h1f y3 ff4 fs0 fc0 sc0 ls68 ws7">via teorema de Pit´<span class="blank _8"></span>agoras, <span class="ff8 wsb">R<span class="ff3 fs1 ls6a ve">2</span></span><span class="lsb">=<span class="ff2 ls1d">z<span class="ff3 fs1 ls12 ve">2</span></span><span class="ls13">+<span class="ff2 ls2a">ρ<span class="ff3 fs1 ls15 ve">2</span></span></span></span><span class="ws13">.<span class="blank _17"> </span>Sendo assim,</span></div><div class="t m0 x40 h6 ydd ff2 fs0 fc0 sc0 ls68 ws1a">V<span class="ff3 fs1 ws5c v1">plano </span><span class="ff4 ls6b">=<span class="ls68 va">1</span></span></div><div class="t m0 x67 h20 yde ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 ls1b v1">0</span><span class="ffa ls6c vc">Z</span><span class="ff3 fs1 ws1b v20">2<span class="ff9">π</span></span></span></div><div class="t m0 x23 h17 ydf ff3 fs1 fc0 sc0 ls68">0</div><div class="t m0 xd h21 ydd ff2 fs0 fc0 sc0 ls68 ws5d">dθ <span class="ffa ls6c v10">Z</span><span class="ffb fs1 v21">∞</span></div><div class="t m0 x2d h17 ydf ff3 fs1 fc0 sc0 ls68">0</div><div class="t m0 x26 h2 ye0 ff8 fs0 fc0 sc0 lsc">−<span class="ff2 ls68 ws10">q d</span></div><div class="t m0 x1e h22 ye1 ff4 fs0 fc0 sc0 ls38">2<span class="ff2 ls5d">π</span><span class="ls68 wsf">(<span class="ff2 ls2a">ρ<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+</span><span class="ff2 ws1a">d<span class="ff3 fs1 ls5a vb">2</span></span>)<span class="ff3 fs1 ws1b vb">3<span class="ff9 ls17">/</span>2</span></span></div><div class="t m0 x68 h2 ye0 ff2 fs0 fc0 sc0 ls68 ws5e">ρ dρ</div><div class="t m0 x69 h22 ye1 ff4 fs0 fc0 sc0 ls16">(<span class="ff2 ls1d">z<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+<span class="ff2 ls2a">ρ<span class="ff3 fs1 ls15 vb">2</span></span><span class="ls68 wsf">)<span class="ff3 fs1 ls21 vb">1<span class="ff9 ls68 ws23">/<span class="ff3">2</span></span></span></span></span></div><div class="t m0 x6a h6 ye2 ff4 fs0 fc0 sc0 ls6d">=<span class="ff8 lsc va">−<span class="ff2 ls68 ws10">q d</span></span></div><div class="t m0 x67 h23 ye3 ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 ls1b v1">0</span><span class="ffa ls6c vc">Z</span><span class="ffb fs1 v20">∞</span></span></div><div class="t m0 x23 h17 ye4 ff3 fs1 fc0 sc0 ls68">0</div><div class="t m0 x3b h2 ye5 ff2 fs0 fc0 sc0 ls68 ws5e">ρ dρ</div><div class="t m0 xd h22 ye6 ff4 fs0 fc0 sc0 ls16">(<span class="ff2 ls2a">ρ<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls26">+<span class="ff2 ls52">d<span class="ff3 fs1 ls15 vb">2</span></span></span>)<span class="ff3 fs1 ls68 ws1b vb">3<span class="ff9 ls17">/<span class="ff3 ls15">2</span></span></span><span class="ls68 wsf">(<span class="ff2 ls34">z<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+</span><span class="ff2 ws1a">ρ<span class="ff3 fs1 ls5a vb">2</span></span>)<span class="ff3 fs1 ws1b vb">1<span class="ff9 ls17">/</span>2</span></span></div><div class="t m0 x6a h6 ye7 ff4 fs0 fc0 sc0 ls6d">=<span class="ff8 lsc va">−<span class="ff2 ls68 ws10">q d</span></span></div><div class="t m0 x67 h2 ye8 ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 v1">0</span></span></div><div class="t m0 x17 h24 ye9 ff4 fs0 fc0 sc0 ls68 wsf">(<span class="ff2 ls2a">ρ<span class="ff3 fs1 ls12 ve">2</span></span><span class="ls13">+<span class="ff2 ls1d">z<span class="ff3 fs1 ls15 ve">2</span></span><span class="ls16">)</span></span><span class="ff3 fs1 ws1b ve">1<span class="ff9 ls17">/</span>2</span></div><div class="t m0 x19 h25 yea ff4 fs0 fc0 sc0 ls16">(<span class="ff2 ls68 ws1a">d<span class="ff3 fs1 ls12 vb">2</span><span class="ff8 ls13">−</span><span class="ls1d">z<span class="ff3 fs1 ls15 vb">2</span></span></span><span class="ls68 wsf">)(<span class="ff2 ls2a">ρ<span class="ff3 fs1 ls12 vb">2</span></span><span class="ls13">+</span><span class="ff2 ws1a">d<span class="ff3 fs1 ls5a vb">2</span></span>)<span class="ff3 fs1 ws1b vb">1<span class="ff9 ls17">/<span class="ff3 ls18">2</span></span></span><span class="ffa v17"></span></span></div><div class="t m0 x37 h14 yeb ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x37 h14 yec ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x37 h14 yed ffa fs0 fc0 sc0 ls68"></div><div class="t m0 x6b h17 yee ff9 fs1 fc0 sc0 ls68 ws23">ρ<span class="ff3 ws1b">=<span class="ffb">∞</span></span></div><div class="t m0 x6b h17 yef ff9 fs1 fc0 sc0 ls68 ws23">ρ<span class="ff3">=0</span></div><div class="t m0 x6a h6 yf0 ff4 fs0 fc0 sc0 ls6d">=<span class="ff8 lsc va">−<span class="ff2 ls68 ws10">q d</span></span></div><div class="t m0 x67 h15 yf1 ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 ls1b v1">0</span><span class="ffa ls6e vf"></span><span class="ff4 v10">1</span></span></div><div class="t m0 x35 h26 yf1 ff4 fs0 fc0 sc0 ls68 wsf">(<span class="ff2 ls52">d<span class="ff3 fs1 ls12 vb">2</span><span class="ff8 ls26">−</span><span class="ls34">z<span class="ff3 fs1 ls15 vb">2</span></span></span><span class="ls6f">)<span class="ff8 ls70 va">−</span></span><span class="ff2 v10">z</span></div><div class="t m0 x9 h15 yf1 ff2 fs0 fc0 sc0 ls68 ws1a">d<span class="ff4 ls16">(</span>d<span class="ff3 fs1 ls12 vb">2</span><span class="ff8 ls13">−</span><span class="ls1d">z<span class="ff3 fs1 ls5a vb">2</span><span class="ff4 ls71">)</span></span><span class="ffa vf"></span></div><div class="t m0 x6a h10 yf2 ff4 fs0 fc0 sc0 ls6d">=<span class="ff8 lsc va">−<span class="ff2 ls68 ws10">q d</span></span></div><div class="t m0 x67 h11 yf3 ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 ls1b v1">0</span><span class="ffa ls72 vf"></span><span class="ls73 v10">d<span class="ff8 ls13">−</span></span><span class="v10">z</span></span></div><div class="t m0 x35 h11 yf3 ff2 fs0 fc0 sc0 ls68 ws1a">d<span class="ff4 ls16">(</span>d<span class="ff3 fs1 ls12 vb">2</span><span class="ff8 ls13">−</span><span class="ls1d">z<span class="ff3 fs1 ls15 vb">2</span><span class="ff4 ls74">)<span class="ffa ls23 vf"></span><span class="ls75 va">=</span><span class="ff8 lsc v10">−</span></span></span><span class="v10">q</span></div><div class="t m0 x8 h5 yf3 ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 ls15 v1">0</span></span><span class="ls16">(<span class="ff2 ls73">d</span><span class="ls13">+<span class="ff2 ls1d">z</span><span class="ls74">)<span class="ff2 ls68 va">.</span></span></span></span></div><div class="t m0 x0 h2 yf4 ff4 fs0 fc0 sc0 ls68 ws7">Somando ao p<span class="blank _5"> </span>otencial gerado pela carga (no eixo<span class="blank _d"> </span><span class="ff2 ls1d">z</span>):</div><div class="t m0 x19 h10 yf5 ff2 fs0 fc0 sc0 ls76">V<span class="ff3 fs1 ls68 ws5f v1">carga </span><span class="ff4 ls77">=</span><span class="ls68 va">q</span></div><div class="t m0 x15 h5 yf6 ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ws10">π <span class="ff3 fs1 ls15 v1">0</span><span class="ff8 wsb">|</span><span class="ls51">z<span class="ff8 ls26">−</span><span class="ls52">d<span class="ff8 ls78">|</span></span></span><span class="va">,</span></span></div><div class="t m0 x0 h2 yf7 ff4 fs0 fc0 sc0 ls68">obtemos</div><div class="t m0 x6c h6 yf8 ff2 fs0 fc0 sc0 ls79">V<span class="ff4 ls7a">=<span class="ff8 lsc va">−</span></span><span class="ls68 va">q</span></div><div class="t m0 x30 h26 yf9 ff4 fs0 fc0 sc0 ls38">4<span class="ff2 ls68 ws10">π <span class="ff3 fs1 ls15 v1">0</span></span><span class="ls16">(<span class="ff2 ls73">d</span><span class="ls13">+<span class="ff2 ls1d">z</span><span class="ls6f">)<span class="ls7b va">+</span><span class="ff2 ls68 v10">q</span></span></span></span></div><div class="t m0 x3a h5 yf9 ff4 fs0 fc0 sc0 ls68 wsf">4<span class="ff2 ws10">π <span class="ff3 fs1 ls5a v1">0</span><span class="ff8 wsb">|</span><span class="ls43">z<span class="ff8 ls13">−</span></span><span class="ws1a">d<span class="ff8 ls78">|</span><span class="va">.</span></span></span></div><div class="t m0 x0 h2 yfa ff4 fs0 fc0 sc0 ls68 ws60">Comparando ao resultado encon<span class="blank _0"></span>trado no item (a),<span class="blank _9"> </span>para</div><div class="t m0 x0 h2 yfb ff4 fs0 fc0 sc0 ls68 ws7">p<span class="blank _5"> </span>on<span class="blank _0"></span>tos sobre o eixo <span class="ff2 ls1d">z</span>, ou seja, com</div><div class="t m0 x6d h12 yfc ff8 fs0 fc0 sc0 ls68 wsb">R<span class="ffb fs1 ls41 v1">±</span><span class="ff4 lsb">=<span class="ffa ls5 v15">q</span><span class="ls68 wsf">0<span class="ff3 fs1 ls12 vb">2</span><span class="ws4c">+ 0<span class="ff3 fs1 ls25 vb">2</span>+ (<span class="ff2 ls43">z</span></span></span></span><span class="ls26">∓<span class="ff2 ls52">d</span></span><span class="ff4 wsf">)<span class="ff3 fs1 ls6a v16">2</span><span class="lsb">=</span></span>|<span class="ff2 ls51">z</span><span class="ls26">∓<span class="ff2 ls52">d</span></span>|<span class="ff2">,</span></div><div class="t m0 x0 h2 yfd ff4 fs0 fc0 sc0 ls68 ws7">v<span class="blank _0"></span>erificamos a equiv<span class="blank _3"></span>alˆ<span class="blank _6"></span>encia.</div><div class="t m0 x0 h27 yfe ff1 fs0 fc0 sc0 ls68 ws61">Problema 2:<span class="blank _a"> </span><span class="ff4 ws62">O camp<span class="blank _5"> </span>o el´<span class="blank _6"></span>etrico<span class="blank _4"> </span><span class="ff2 v22">~</span></span></div><div class="t m0 x1d h2 yfe ff2 fs0 fc0 sc0 ls7c">E<span class="ff4 ls68 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws63">) gerado p<span class="blank _5"> </span>or uma dis-</span></span></span></div><div class="t m0 x0 h2 yff ff4 fs0 fc0 sc0 ls68 ws64">tribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao estacion´<span class="blank _6"></span>aria de cargas <span class="ff2 ls2a">ρ</span><span class="wsf">(<span class="ff2 ws3c">~<span class="blank _6"></span>r <span class="ff4 ws64">) dev<span class="blank _0"></span>e satisfazer a duas</span></span></span></div><div class="t m0 x0 h2 y100 ff4 fs0 fc0 sc0 ls68 wsf">equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes:</div><div class="t m0 x67 h27 y101 ff8 fs0 fc0 sc0 ls68 ws65">∇ ·<span class="blank _d"> </span><span class="ff2 v22">~</span></div><div class="t m0 x1a h6 y101 ff2 fs0 fc0 sc0 ls7d">E<span class="ff4 ls7e">=</span><span class="ls68 va">ρ</span></div><div class="t m0 x22 h2 y102 ff2 fs0 fc0 sc0 lsd"><span class="ff3 fs1 ls68 v1">0</span></div><div class="t m0 x20 h27 y101 ff4 fs0 fc0 sc0 ls7f">e<span class="ff8 ls68 ws65">∇ ×<span class="blank _d"> </span><span class="ff2 v22">~</span></span></div><div class="t m0 x8 h2 y101 ff2 fs0 fc0 sc0 ls7d">E<span class="ff4 ls68 wsc">= 0<span class="ff2">.</span></span></div><div class="t m0 x0 h27 y103 ff4 fs0 fc0 sc0 ls68 ws66">(a) A partir destas, escrev<span class="blank _0"></span>a<span class="blank _9"> </span><span class="ff2 v22">~</span></div><div class="t m0 x29 h2 y103 ff2 fs0 fc0 sc0 ls7c">E<span class="ff4 ls68 wsf">(<span class="blank _0"></span><span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws66">) em termos do p<span class="blank _5"> </span>otencial</span></span></span></div><div class="t m0 x0 h2 y104 ff4 fs0 fc0 sc0 ls68 ws67">el<span class="blank _0"></span>´<span class="blank _6"></span>etrico <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws3c">~<span class="blank _6"></span>r <span class="ff4 ws68">) e mostre que, na ausˆ<span class="blank _6"></span>encia de cargas, o p<span class="blank _5"> </span>oten-</span></span></span></div><div class="t m0 x0 h1f y105 ff4 fs0 fc0 sc0 ls68 ws7">cial dev<span class="blank _0"></span>e ob<span class="blank _5"> </span>edecer `<span class="blank _8"></span>a Equa¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao de Laplace <span class="ff8 ls80">∇<span class="ff3 fs1 ls15 ve">2</span><span class="ff2 ls7">V</span></span><span class="wsc">= 0<span class="blank _1d"> </span>(1,00).</span></div><div class="t m0 x0 h2 y106 ff4 fs0 fc0 sc0 ls68 ws69">(b) Em co<span class="blank _5"> </span>ordenadas cartesianas, e assumindo que tratamos</div><div class="t m0 x0 h2 y107 ff4 fs0 fc0 sc0 ls68 ws6a">de um problema bidimensional, <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ls81">)<span class="ff8 ls82">→</span></span><span class="ls2f">V<span class="ff4 ls16">(</span></span><span class="ws6b">x,<span class="blank _c"> </span>y <span class="ff4 ws6c">). Mostre</span></span></span></span></div><div class="t m0 x0 h2 y108 ff4 fs0 fc0 sc0 ls68 ws6d">que, imp<span class="blank _5"> </span>ondo separa¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao de v<span class="blank _3"></span>ari´<span class="blank _6"></span>aveis, ou seja, escrevendo</div><div class="t m0 x0 h2 y109 ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws19">x,<span class="blank _c"> </span>y <span class="ff4 ws2a">) = </span><span class="ls83">X</span><span class="ff4 wsf">(</span><span class="ls11">x<span class="ff4 ls16">)</span><span class="ls84">Y</span></span><span class="ff4 wsf">(</span><span class="ls14">y</span><span class="ff4 ws7">), p<span class="blank _5"> </span>odemos concluir que, em geral,</span></span></div><div class="t m0 x3d hc y10a ff2 fs0 fc0 sc0 ls85">X<span class="ff4 ls68 wsf">(</span><span class="ls11">x<span class="ff4 ls68 ws2a">) = </span><span class="ls86">A<span class="ff9 fs1 ls87 v1">x</span><span class="ls88">e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 ws23">k<span class="ffc fs2 ls89 v23">x</span><span class="ls8a">x</span></span></span><span class="ff4 ls13">+</span><span class="ls8b">B<span class="ff9 fs1 ls87 v1">x</span></span>e<span class="ffb fs1 ls68 ws2f v12">−<span class="ff9 ls8c">k<span class="ffc fs2 ls8d v23">x</span><span class="ls87">x</span></span></span><span class="ls68">,</span></span></span></span></div><div class="t m0 x3d hc y10b ff2 fs0 fc0 sc0 ls84">Y<span class="ff4 ls68 wsf">(</span><span class="ls14">y<span class="ff4 ls68 ws2a">) = </span><span class="ls86">A<span class="ff9 fs1 ls8e v1">y</span><span class="ls88">e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="ls90">y</span></span></span><span class="ff4 ls26">+</span><span class="ls8b">B<span class="ff9 fs1 ls8e v1">y</span></span>e<span class="ffb fs1 ls68 ws2f v12">−<span class="ff9 ls8c">k<span class="ffc fs2 ls8f v23">y</span><span class="ls8e">y</span></span></span><span class="ls68">,</span></span></span></span></div><div class="t m0 x0 h2 y10c ff4 fs0 fc0 sc0 ls68 ws6e">em que <span class="ff2 ls86">A<span class="ff9 fs1 ls87 v1">x</span></span><span class="ls91">,<span class="ff2 ls86">A<span class="ff9 fs1 ls8e v1">y</span></span><span class="ls92">,<span class="ff2 ls8b">B<span class="ff9 fs1 ls87 v1">x</span></span>,<span class="ff2 ls8b">B<span class="ff9 fs1 ls8e v1">y</span></span></span>,</span><span class="ff2 ws1a">k<span class="ff9 fs1 ls93 v1">x</span></span><span class="ls94">e<span class="ff2 ls95">k<span class="ff9 fs1 ls96 v1">y</span></span></span>s˜<span class="blank _8"></span>ao constantes arbitr´<span class="blank _8"></span>arias,</div><div class="t m0 x0 h1f y10d ff4 fs0 fc0 sc0 ls68 ws7">com a<span class="blank _d"> </span>´<span class="blank _8"></span>unica restri¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao <span class="ff2 ls97">k</span><span class="ff3 fs1 ve">2</span></div><div class="t m0 x17 h28 y10e ff9 fs1 fc0 sc0 ls98">x<span class="ff4 fs0 ls13 v22">+<span class="ff2 ls97">k</span></span><span class="ff3 ls68 v13">2</span></div><div class="t m0 x1f h29 y10e ff9 fs1 fc0 sc0 ls99">y<span class="ff4 fs0 ls68 wsc v22">= 0.<span class="blank _1d"> </span>(2,00)</span></div><div class="t m0 x0 h2 y10f ff1 fs0 fc0 sc0 ls68 ws6f">Resolu¸<span class="blank _8"></span>c˜<span class="blank _14"></span>ao do Problema 2:<span class="blank _18"> </span><span class="ff4 ws70">(a) Conhecendo a identidade</span></div><div class="t m0 x0 h2 y110 ff4 fs0 fc0 sc0 ls68 ws71">matem´<span class="blank _8"></span>atica <span class="ff8 ws72">∇ × </span><span class="wsf">(<span class="ff8 ls80">∇<span class="ff2 ls9a">φ</span></span><span class="ws73">) = 0,<span class="blank _20"> </span>em que<span class="blank _a"> </span><span class="ff2 ls9b">φ</span><span class="ws4">´<span class="blank _6"></span>e qualquer fun¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao</span></span></span></div><div class="t m0 x0 h2a yda ff4 fs0 fc0 sc0 ls68 ws6a">escalar, para satisfazermos <span class="ff8 ws74">∇ ×<span class="blank _17"> </span><span class="ff2 v22">~</span></span></div><div class="t m0 x1d h2a yda ff2 fs0 fc0 sc0 ls9c">E<span class="ff4 ls68 ws5b">= 0,<span class="blank _17"> </span>basta escrever<span class="blank _9"> </span><span class="ff2 v22">~</span></span></div><div class="t m0 x6e h2 yda ff2 fs0 fc0 sc0 ls68">E</div><div class="t m0 x0 h2 ydb ff4 fs0 fc0 sc0 ls68 ws75">como o gradien<span class="blank _0"></span>te de uma fun¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao escalar.<span class="blank _21"> </span>Em particular,</div><div class="t m0 x0 h2 ydc ff4 fs0 fc0 sc0 ls68 ws13">escolhe-se tal fun¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao como <span class="ff8 lsc">−<span class="ff2 ls2f">V</span></span><span class="wsf">(<span class="ff2 ws12">~<span class="blank _6"></span>r <span class="ff4 ws13">), em que </span><span class="ls9d">V</span><span class="ff4 ws18">´<span class="blank _2"></span>e<span class="blank _10"> </span>o<span class="blank _1d"> </span>p otencial</span></span></span></div><div class="t m0 x43 h27 y1 ff4 fs0 fc0 sc0 ls68 ws76">el<span class="blank _0"></span>´<span class="blank _6"></span>etrico.<span class="blank _17"> </span>T<span class="blank _3"></span>emos, assim,<span class="blank _17"> </span><span class="ff2 v22">~</span></div><div class="t m0 x6f h2 y1 ff2 fs0 fc0 sc0 ls7d">E<span class="ff4 lsb">=<span class="ff8 ls68 wsb">−∇</span></span><span class="ls2f">V<span class="ff4 ls68 ws6e">.<span class="blank _a"> </span>Como o camp<span class="blank _5"> </span>o el´<span class="blank _6"></span>etrico</span></span></div><div class="t m0 x43 h27 y2 ff4 fs0 fc0 sc0 ls68 ws77">tam<span class="blank _0"></span>b´<span class="blank _8"></span>em satisfaz <span class="ff8 ws78">∇ ·<span class="blank _1d"> </span><span class="ff2 v22">~</span></span></div><div class="t m0 x70 h2b y2 ff2 fs0 fc0 sc0 ls7d">E<span class="ff4 ls9e">=<span class="ff9 fs1 ls68 v24">ρ</span></span></div><div class="t m0 x71 h2c y111 ff9 fs1 fc0 sc0 ls9f"><span class="ffd fs2 lsa0 v23">0</span><span class="ff4 fs0 ls68 ws79 ve">, em termos de <span class="ff2 ls2f">V</span><span class="ws7a">, esta equa¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao</span></span></div><div class="t m0 x43 h2 y3 ff4 fs0 fc0 sc0 ls68">torna-se</div><div class="t m0 x46 hc y112 ff8 fs0 fc0 sc0 ls68 ws65">∇ · <span class="ff4 ls16">(</span><span class="wsb">−∇<span class="ff2 ls2f">V</span><span class="ff4 ws2a">) = <span class="ff2 ws1a">ρ/<span class="ff3 fs1 ls6a v1">0</span></span><span class="wsf">=<span class="blank _22"></span><span class="ff8 ws7b">⇒ ∇<span class="ff3 fs1 ls15 v12">2</span><span class="ff2 ls7">V<span class="ff4 lsb">=</span></span><span class="lsc">−</span><span class="ff2 ws1a">ρ/<span class="ff3 fs1 ls15 v1">0</span>.</span></span></span></span></span></div><div class="t m0 x43 h2 y113 ff4 fs0 fc0 sc0 ls68 ws57">Na aus<span class="blank _0"></span>ˆ<span class="blank _6"></span>encia de cargas,<span class="blank _18"> </span><span class="ff2 lsa1">ρ</span>= 0, esta equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao se transforma</div><div class="t m0 x43 h2 y114 ff4 fs0 fc0 sc0 ls68 ws7">na Equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao de Laplace.</div><div class="t m0 x43 h2 y115 ff4 fs0 fc0 sc0 ls68 ws7c">(b) Substituindo <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws19">x,<span class="blank _c"> </span>y </span><span class="ws7d">) = <span class="ff2 ls85">X</span></span>(<span class="ff2 ls11">x</span>)<span class="ff2 ls84">Y</span>(<span class="ff2 ls14">y</span><span class="ws49">) na Equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao de</span></span></div><div class="t m0 x43 h2 y116 ff4 fs0 fc0 sc0 ls68 ws7">Laplace, e arranjado-a con<span class="blank _0"></span>venien<span class="blank _3"></span>temente, encon<span class="blank _3"></span>tramos</div><div class="t m0 x5a h24 y117 ff2 fs0 fc0 sc0 lsa2">∂<span class="ff3 fs1 ls68 ve">2</span></div><div class="t m0 x72 h2d y118 ff2 fs0 fc0 sc0 ls68 ws14">∂ x<span class="ff3 fs1 ls18 vb">2</span><span class="ls83 va">X<span class="ff4 ls16">(</span></span><span class="ws1a va">x<span class="ff4 ls16">)<span class="ff2 ls84">Y</span><span class="ls68 wsf">(<span class="ff2 ls14">y</span><span class="ws4c">) +<span class="blank _23"> </span></span></span></span></span><span class="lsa2 v10">∂</span><span class="ff3 fs1 v11">2</span></div><div class="t m0 x73 h5 y118 ff2 fs0 fc0 sc0 ls68 ws7e">∂ y <span class="ff3 fs1 ls18 vb">2</span><span class="ls83 va">X<span class="ff4 ls16">(<span class="ff2 ls11">x</span><span class="ls68 wsf">)<span class="ff2 ls84">Y</span>(<span class="ff2 ls14">y</span><span class="lsa3 ws7f">)=0<span class="blank _24"></span><span class="ff2 ls68">.</span></span></span></span></span></div><div class="t m0 x43 h2 y119 ff4 fs0 fc0 sc0 ls68 ws18">Dividindo-a<span class="blank _1d"> </span>p or<span class="blank _1d"> </span><span class="ff2 ls85">X</span><span class="wsf">(<span class="ff2 ls11">x</span>)<span class="ff2 ls84">Y</span>(<span class="ff2 ls14">y</span><span class="ws7">) temos</span></span></div><div class="t m0 x74 h2 y11a ff4 fs0 fc0 sc0 ls68">1</div><div class="t m0 x5a h2 y11b ff2 fs0 fc0 sc0 ls85">X<span class="ff4 ls68 wsf">(</span><span class="ls11">x<span class="ff4 ls68">)</span></span></div><div class="t m0 x75 h24 y11a ff2 fs0 fc0 sc0 lsa2">∂<span class="ff3 fs1 ls15 ve">2</span><span class="ls85">X<span class="ff4 ls68 wsf">(</span><span class="ls11">x<span class="ff4 ls68">)</span></span></span></div><div class="t m0 x76 h2e y11b ff2 fs0 fc0 sc0 ls68 ws14">∂ x<span class="ff3 fs1 lsa4 vb">2</span><span class="ff4 lsa5 va">+</span><span class="ff4 v10">1</span></div><div class="t m0 x77 h2 y11b ff2 fs0 fc0 sc0 ls84">Y<span class="ff4 ls68 wsf">(</span><span class="ls14">y<span class="ff4 ls68">)</span></span></div><div class="t m0 x60 h24 y11a ff2 fs0 fc0 sc0 lsa6">∂<span class="ff3 fs1 ls5a ve">2</span><span class="lsa7">Y<span class="ff4 ls16">(</span><span class="ls14">y<span class="ff4 ls68">)</span></span></span></div><div class="t m0 x78 h5 y11b ff2 fs0 fc0 sc0 ls68 ws80">∂ y <span class="ff3 fs1 lsa8 vb">2</span><span class="ff4 wsc va">= 0</span><span class="va">.</span></div><div class="t m0 x43 h2 y11c ff4 fs0 fc0 sc0 ls68 ws81">Note que o primeiro termo do lado esquerdo da ´<span class="blank _8"></span>ultima</div><div class="t m0 x43 h2 y11d ff4 fs0 fc0 sc0 ls68 ws82">equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao s´<span class="blank _6"></span>o dep<span class="blank _5"> </span>ende da v<span class="blank _3"></span>ari´<span class="blank _6"></span>av<span class="blank _0"></span>el <span class="ff2 ls11">x</span>, e o segundo s´<span class="blank _8"></span>o dep<span class="blank _5"> </span>ende</div><div class="t m0 x43 h2 y11e ff4 fs0 fc0 sc0 ls68 ws83">de <span class="ff2 ls14">y</span><span class="ws84">.<span class="blank _23"> </span>Portan<span class="blank _3"></span>to,<span class="blank _a"> </span>para que a igualdade seja satisfeita inde-</span></div><div class="t m0 x43 h2 y11f ff4 fs0 fc0 sc0 ls68 ws7">p<span class="blank _5"> </span>enden<span class="blank _0"></span>temen<span class="blank _0"></span>te dos v<span class="blank _3"></span>alores de <span class="ff2 lsa9">x</span><span class="lsaa">e<span class="ff2 ls14">y</span></span>, ´<span class="blank _6"></span>e natural admitir que</div><div class="t m0 x43 h2 y120 ff4 fs0 fc0 sc0 ls68 ws7">os dois termos sejam iguais a uma constante:</div><div class="t m0 x79 h2 y121 ff4 fs0 fc0 sc0 ls68">1</div><div class="t m0 x66 h2 y122 ff2 fs0 fc0 sc0 ls83">X<span class="ff4 ls16">(</span><span class="ls11">x<span class="ff4 ls68">)</span></span></div><div class="t m0 x7a h24 y121 ff2 fs0 fc0 sc0 lsa2">∂<span class="ff3 fs1 ls15 ve">2</span><span class="ls85">X<span class="ff4 ls68 wsf">(</span><span class="ls11">x<span class="ff4 ls68">)</span></span></span></div><div class="t m0 x4e h2f y122 ff2 fs0 fc0 sc0 ls68 ws14">∂ x<span class="ff3 fs1 lsab vb">2</span><span class="ff4 lsb va">=</span><span class="ls97 va">k</span><span class="ff3 fs1 v21">2</span></div><div class="t m0 x7b h30 y123 ff9 fs1 fc0 sc0 lsac">x<span class="ff4 fs0 lsad v22">e<span class="ls68 va">1</span></span></div><div class="t m0 x5f h2 y122 ff2 fs0 fc0 sc0 ls84">Y<span class="ff4 ls68 wsf">(</span><span class="ls14">y<span class="ff4 ls68">)</span></span></div><div class="t m0 x7c h24 y121 ff2 fs0 fc0 sc0 lsa2">∂<span class="ff3 fs1 ls15 ve">2</span><span class="ls84">Y<span class="ff4 ls68 wsf">(</span><span class="ls14">y<span class="ff4 ls68">)</span></span></span></div><div class="t m0 x7d h2f y122 ff2 fs0 fc0 sc0 ls68 ws7e">∂ y <span class="ff3 fs1 lsae vb">2</span><span class="ff4 lsb va">=</span><span class="lsaf va">k</span><span class="ff3 fs1 v21">2</span></div><div class="t m0 x7e h29 y123 ff9 fs1 fc0 sc0 ls8e">y<span class="ff2 fs0 ls68 v22">,</span></div><div class="t m0 x43 h1f y124 ff4 fs0 fc0 sc0 ls68 ws85">com <span class="ff2 ls97">k</span><span class="ff3 fs1 ve">2</span></div><div class="t m0 x7f h28 y125 ff9 fs1 fc0 sc0 lsb0">x<span class="ff4 fs0 lsb1 v22">+<span class="ff2 ls97">k</span></span><span class="ff3 ls68 v13">2</span></div><div class="t m0 x80 h29 y125 ff9 fs1 fc0 sc0 lsb2">y<span class="ff4 fs0 ls68 ws86 v22">=<span class="blank _10"> </span>0.<span class="blank _9"> </span>A forma das constan<span class="blank _3"></span>tes ´<span class="blank _6"></span>e atribu<span class="blank _1"></span>´<span class="blank _7"></span>ıda p<span class="blank _5"> </span>or</span></div><div class="t m0 x43 h2 y126 ff4 fs0 fc0 sc0 ls68 ws87">futura con<span class="blank _0"></span>veni<span class="blank _3"></span>ˆ<span class="blank _2"></span>encia.En<span class="blank _3"></span>t˜<span class="blank _6"></span>ao,<span class="blank _a"> </span>as equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes para <span class="ff2 ls85">X</span><span class="wsf">(<span class="ff2 ls11">x</span></span>) e <span class="ff2 lsa7">Y</span><span class="ls16">(<span class="ff2 ls14">y</span></span>)</div><div class="t m0 x43 h2 y127 ff4 fs0 fc0 sc0 ls68">tornam-se</div><div class="t m0 x81 h1f y128 ff2 fs0 fc0 sc0 lsa2">∂<span class="ff3 fs1 ls15 ve">2</span><span class="ls68">X</span></div><div class="t m0 x82 h31 y129 ff2 fs0 fc0 sc0 ls68 ws14">∂ x<span class="ff3 fs1 lsb3 vb">2</span><span class="ff4 lsb va">=</span><span class="lsaf va">k</span><span class="ff3 fs1 v21">2</span></div><div class="t m0 x6f h32 y12a ff9 fs1 fc0 sc0 ls87">x<span class="ff2 fs0 lsb4 v22">X<span class="ff4 lsb5">e<span class="ff2 lsa2 va">∂</span></span></span><span class="ff3 ls15 v15">2</span><span class="ff2 fs0 ls68 v25">Y</span></div><div class="t m0 x54 h31 y129 ff2 fs0 fc0 sc0 ls68 ws7e">∂ y <span class="ff3 fs1 lsb6 vb">2</span><span class="ff4 lsb va">=</span><span class="ls97 va">k</span><span class="ff3 fs1 v21">2</span></div><div class="t m0 x83 h29 y12a ff9 fs1 fc0 sc0 lsb7">y<span class="ff2 fs0 ls68 ws14 v22">Y ,</span></div><div class="t m0 x43 h2 y12b ff4 fs0 fc0 sc0 ls68 ws88">de mo<span class="blank _5"> </span>do que as solu¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes apresentadas no en<span class="blank _3"></span>unciado s˜<span class="blank _6"></span>ao</div><div class="t m0 x43 h2 y12c ff4 fs0 fc0 sc0 ls68 ws13">diretamen<span class="blank _0"></span>te verificadas.</div><div class="t m0 x43 h2 y12d ff1 fs0 fc0 sc0 ls68 ws89">Problema 3:<span class="blank _25"> </span><span class="ff4 ws8a">Duas placas condutoras planas,<span class="blank _20"> </span>aterradas</span></div><div class="t m0 x43 h2 y12e ff4 fs0 fc0 sc0 ls68 ws8b">e de ´<span class="blank _8"></span>area infinita est˜<span class="blank _6"></span>ao lo<span class="blank _5"> </span>calizadas em <span class="ff2 lsb8">y</span>=<span class="blank _26"> </span>0 e <span class="ff2 lsb8">y</span><span class="lsb9">=<span class="ff2 lsba">a</span></span>.</div><div class="t m0 x43 h2 y12f ff4 fs0 fc0 sc0 ls68 ws8c">Em <span class="ff2 lsbb">x</span><span class="lsbc">=<span class="ff8 lsc">−<span class="ff2 lsbd">b</span></span><span class="lsbe">e<span class="ff2 lsbb">x</span></span></span><span class="ws8d">= +<span class="ff2 ls20">b</span><span class="ws8e">,<span class="blank _23"> </span>elas s˜<span class="blank _8"></span>ao conectadas p<span class="blank _5"> </span>or tiras</span></span></div><div class="t m0 x43 h2 y130 ff4 fs0 fc0 sc0 ls68 ws8f">met´<span class="blank _8"></span>alicas de comprimento infinito, man<span class="blank _0"></span>tidas em p<span class="blank _5"> </span>otencial</div><div class="t m0 x43 h2 y131 ff4 fs0 fc0 sc0 ls68 ws90">constan<span class="blank _0"></span>te <span class="ff2 ls76">V<span class="ff3 fs1 ls15 v1">0</span></span><span class="ws91">.<span class="blank _20"> </span>Estamos in<span class="blank _0"></span>teressados em a<span class="blank _0"></span>v<span class="blank _3"></span>aliar o p<span class="blank _5"> </span>otencial</span></div><div class="t m0 x43 h2 y132 ff4 fs0 fc0 sc0 ls68 ws92">el<span class="blank _0"></span>´<span class="blank _6"></span>etrico no interior do tubo infinito,<span class="blank _d"> </span>e de se¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao retangular,</div><div class="t m0 x43 h2 y133 ff4 fs0 fc0 sc0 ls68 ws7">formado p<span class="blank _5"> </span>or tais placas condutoras (v<span class="blank _0"></span>eja a figura abaixo).</div><div class="t m0 x43 h2 y134 ff4 fs0 fc0 sc0 ls68 ws93">(a) Justifique o fato de p<span class="blank _5"> </span>odermos tratar tal<span class="blank _23"> </span>problema</div><div class="t m0 x43 h2 y135 ff4 fs0 fc0 sc0 ls68 ws94">em ap<span class="blank _5"> </span>enas duas dimens˜<span class="blank _8"></span>oes,<span class="blank _17"> </span>o que nos p<span class="blank _5"> </span>ermite utilizar as</div><div class="t m0 x43 h2 y136 ff4 fs0 fc0 sc0 ls68 ws7">equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes do problema anterior. (0,50)</div><div class="t m0 x43 h2 y137 ff4 fs0 fc0 sc0 ls68 ws95">(b) Indique to<span class="blank _5"> </span>das as condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes de contorno pertinentes para</div><div class="t m0 x43 h2 y138 ff4 fs0 fc0 sc0 ls68 ws7">este problema. (1,50)</div><div class="t m0 x43 h2 y139 ff4 fs0 fc0 sc0 ls68 ws96">(c) Mostre que a express˜<span class="blank _8"></span>ao para <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws19">x,<span class="blank _c"> </span>y </span></span>) no interior to tubo</div><div class="t m0 x43 h2 y13a ff4 fs0 fc0 sc0 ls68 ws7">tem a seguin<span class="blank _0"></span>te forma</div><div class="t m0 x43 h6 y13b ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws19">x,<span class="blank _c"> </span>y <span class="ff4 wsc">) =<span class="blank _18"> </span><span class="ls38 va">4</span></span><span class="ws1a va">V</span><span class="ff3 fs1 v16">0</span></span></div><div class="t m0 x80 h33 y13c ff2 fs0 fc0 sc0 lsbf">π<span class="ffa ls68 v26">X</span></div><div class="t m0 x82 h17 y13d ff9 fs1 fc0 sc0 ls68 ws23">n<span class="ff3 ws1b">=1</span>,<span class="ff3 ws1b">3</span>,...</div><div class="t m0 x5d h2 y13e ff4 fs0 fc0 sc0 ls68">1</div><div class="t m0 x84 h2 y13c ff2 fs0 fc0 sc0 ls68">n</div><div class="t m0 x71 h2 y13e ff4 fs0 fc0 sc0 ls68 wsf">cosh(<span class="ff2 ws10">nπ x/a</span>)</div><div class="t m0 x71 h5 y13c ff4 fs0 fc0 sc0 ls68 wsf">cosh(<span class="ff2 ws10">nπ b/a</span><span class="lsc0">)</span><span class="va">sen(<span class="ff2 ws10">nπ y /a<span class="ff4 ls16">)</span><span class="lsc1">.</span></span>(2<span class="ff2 ls1a">,</span>00)</span></div><div class="t m0 x85 h2 y13f ff4 fs0 fc0 sc0 ls68">2</div></div><div class="pi" data-data="{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}"></div></div> <div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img fetchpriority="low" loading="lazy" class="bi x41 y0 w3 h1" alt src="https://files.passeidireto.com/ea027e35-c51f-4c05-a101-53e2a349c319/bg3.png" alt="Pré-visualização de imagem de arquivo"><div class="t m0 x0 h2 y1 ff4 fs0 fc0 sc0 ls68 ws13">Dev<span class="blank _0"></span>em ser<span class="blank _d"> </span>´<span class="blank _8"></span>uteis as express˜<span class="blank _8"></span>oes:</div><div class="t m0 x1 h34 y140 ffa fs0 fc0 sc0 ls6c">Z<span class="ff9 fs1 ls68 vd">L</span></div><div class="t m0 x12 h17 y141 ff3 fs1 fc0 sc0 ls68">0</div><div class="t m0 x1b h6 y142 ff4 fs0 fc0 sc0 ls68 wsf">sen(<span class="ff2 ws10">nπ x/L</span><span class="ws7">) sen(<span class="ff2 ws10">mπ x/L</span><span class="lsc2">)</span><span class="ff2 ws97">dx </span><span class="lsc3">=</span><span class="ff2 va">a</span></span></div><div class="t m0 x69 h5 y143 ff4 fs0 fc0 sc0 lsc4">2<span class="ff2 lsc5 va">δ</span><span class="ff9 fs1 ls68 ws98 v27">mn </span><span class="ff2 ls68 va">,</span></div><div class="t m0 x1 h35 y144 ff4 fs0 fc0 sc0 ls68 ws99">cosh <span class="ff2 lsc6">α</span><span class="lsc3">=<span class="ff2 ls88 va">e</span></span><span class="ff3 fs1 ws1b v28">+<span class="ff9 lsc7">α</span></span><span class="ls13 va">+<span class="ff2 ls88">e<span class="ffb fs1 lsc8 ve">−<span class="ff9 ls68">α</span></span></span></span></div><div class="t m0 x2b h36 y145 ff4 fs0 fc0 sc0 lsc9">2<span class="ff2 ls68 va">.</span></div><div class="t m0 x1e h3 y146 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1f h3 y147 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x20 h3 y148 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x21 h3 y149 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xd h3 y14a ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x3c h3 y14b ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1 h3 y14c ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x42 h3 y14d ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x86 h3 y14e ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x41 h3 y14f ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x3c h3 y150 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1 h3 y151 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x42 h3 y152 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x86 h3 y153 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x41 h37 y154 ff5 fs0 fc0 sc0 lsca">H<span class="ls68 v21">H</span></div><div class="t m0 x1 h3 y155 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x42 h3 y156 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x86 h3 y157 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x41 h3 y158 ff5 fs0 fc0 sc0 lscb">H<span class="ls68 v29"></span></div><div class="t m0 xf h3 y159 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x10 h3 y15a ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x11 h3 y15b ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x12 h3 y15c ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x13 h3 y15d ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x2 h3 y15e ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x41 h38 y15f ff5 fs0 fc0 sc0 lscc"><span class="ls68 v2a"></span></div><div class="t m0 x1f h3 y160 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x20 h3 y161 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x21 h3 y162 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x22 h3 y163 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x23 h3 y164 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x3d h3 y165 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x87 h3 y166 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x1e h3 y167 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1f h3 y168 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x20 h3 y169 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x21 h3 y16a ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xd h3 y16b ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x3c h3 y16c ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x1 h3 y16d ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x42 h3 y16e ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x86 h3 y16f ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 x41 h3 y170 ff5 fs0 fc0 sc0 ls68">H</div><div class="t m0 xe h3 y171 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 xf h3 y172 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x10 h3 y173 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x11 h3 y174 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x12 h3 y175 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x13 h3 y176 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x2 h3 y177 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x41 h39 y178 ff5 fs0 fc0 sc0 lscc"><span class="ls68 v2a"></span></div><div class="t m0 x1f h3 y179 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x20 h3 y17a ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x21 h3 y17b ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x22 h3 y17c ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x23 h3 y148 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x3d h3 y17d ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x87 h3 y17e ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x88 h3 y157 ff5 fs0 fc0 sc0 ls68 wsb">-<span class="ff2 v3">x</span></div><div class="t m0 x89 h3 y17f ff5 fs0 fc0 sc0 ls68">6</div><div class="t m0 x8a h2 y180 ff2 fs0 fc0 sc0 ls68">y</div><div class="t m0 x8b h3 y155 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x8c h3 y181 ff5 fs0 fc0 sc0 ls68"></div><div class="t m0 x4 h3 y182 ff5 fs0 fc0 sc0 ls68 wsb"><span class="blank _27"></span><span class="blank _27"></span></div><div class="t m0 x8b h3 y183 ff5 fs0 fc0 sc0 ls68">B</div><div class="t m0 x8c h3 y17f ff5 fs0 fc0 sc0 ls68">B</div><div class="t m0 x8c h3 y184 ff5 fs0 fc0 sc0 ls68 wsb">B<span class="blank _27"></span>M</div><div class="t m0 x12 h4 y156 ff6 fs0 fc0 sc0 ls68 wsb">H<span class="ls5 v3">H</span><span class="v4">H</span><span class="ls5 v2b">H<span class="v3">H</span></span><span class="v6">H</span><span class="ls5 v2c">H<span class="v3">H</span></span><span class="v8">H<span class="v3">H<span class="blank _b"></span>j</span></span></div><div class="t m0 x1d h2 y185 ff2 fs0 fc0 sc0 ls68">x</div><div class="t m0 xa h4 y186 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xb h4 y187 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xc h4 y188 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xd h4 y189 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xe h4 y18a ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 xf h4 y181 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x10 h4 y18b ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x11 h4 y18c ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x12 h4 y182 ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x13 h4 y18d ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x2 h4 y18e ff6 fs0 fc0 sc0 ls68"></div><div class="t m0 x8d h4 y18f ff6 fs0 fc0 sc0 ls68 wsb"><span class="blank _b"></span>)</div><div class="t m0 x86 h2 y190 ff2 fs0 fc0 sc0 ls68">z</div><div class="t m0 x35 h4 y191 ff6 fs0 fc0 sc0 ls68">6</div><div class="t m0 xe h2 y192 ff2 fs0 fc0 sc0 ls68">y</div><div class="t m0 x39 h3a y193 ffe fs3 fc0 sc0 lscd">−<span class="fff lsce">b<span class="ff10 ls68 ws9a">+<span class="fff">b</span></span></span></div><div class="t m0 x8a h3b y194 fff fs3 fc0 sc0 ls68">a</div><div class="t m0 x5 h3b y195 fff fs3 fc0 sc0 ls68 ws9a">V<span class="ff11 fs4 lscf v23">0</span><span class="lsd0">V</span><span class="ff11 fs4 v23">0</span></div><div class="t m0 x6 h3c y191 ff12 fs5 fc0 sc0 lsd1">V<span class="ff13 ls68 ws9b">= 0</span></div><div class="t m0 x6 h3c y151 ff12 fs5 fc0 sc0 lsd1">V<span class="ff13 ls68 ws9b">= 0</span></div><div class="t m0 x0 h2 y196 ff1 fs0 fc0 sc0 ls68 ws9c">Resolu¸<span class="blank _8"></span>c˜<span class="blank _14"></span>ao do Problema 3:<span class="blank _25"> </span><span class="ff4 ws9d">(a) Devemos notar que o</span></div><div class="t m0 x0 h2 y197 ff4 fs0 fc0 sc0 ls68 ws9e">problema<span class="blank _1d"> </span>´<span class="blank _6"></span>e inv<span class="blank _3"></span>arian<span class="blank _0"></span>te se deslo<span class="blank _5"> </span>carmos a origem do sistema</div><div class="t m0 x0 h2 y198 ff4 fs0 fc0 sc0 ls68 ws9f">de co<span class="blank _5"> </span>ordenadas ao longo da dire¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao <span class="ff2 ls34">z</span><span class="wsa0">.<span class="blank _28"> </span>Isto ´<span class="blank _6"></span>e<span class="blank _20"> </span>suficiente</span></div><div class="t m0 x0 h2 y199 ff4 fs0 fc0 sc0 ls68 ws7">para tratar o problema como sendo indep<span class="blank _5"> </span>enden<span class="blank _0"></span>te de <span class="ff2 ls34">z</span>.</div><div class="t m0 x0 h2 y19a ff4 fs0 fc0 sc0 ls68 ws7">(b) Considerando <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws19">x,<span class="blank _c"> </span>y </span></span>), temos as seguin<span class="blank _0"></span>tes condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes:</div><div class="t m0 x8e h2 y19b ff4 fs0 fc0 sc0 ls68 wsa1">1) <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws30">x, y<span class="blank _10"> </span></span><span class="wsc">= 0) = 0;<span class="blank _29"> </span>2)<span class="blank _2a"> </span><span class="ff2 ls8">V</span></span>(<span class="ff2 ws30">x, y<span class="blank _10"> </span></span><span class="lsb">=</span><span class="ff2 ws1a">a</span><span class="wsc">) = 0;</span></span></div><div class="t m0 x8e h2 y19c ff4 fs0 fc0 sc0 ls68 wsa1">3) <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 lsd2">x</span><span class="lsb">=<span class="ff8 lsc">−</span></span><span class="ff2 wsa2">b,<span class="blank _c"> </span>y </span><span class="wsa3">) = <span class="ff2 ls76">V<span class="ff3 fs1 ls15 v1">0</span></span><span class="wsa4">;<span class="blank _19"> </span>4) <span class="ff2 ls8">V</span></span></span>(<span class="ff2 lsd2">x</span><span class="wsc">= +<span class="ff2 wsa2">b,<span class="blank _c"> </span>y </span><span class="wsa3">) = <span class="ff2 ls76">V<span class="ff3 fs1 ls15 v1">0</span><span class="ls68">.</span></span></span></span></span></div><div class="t m0 x0 h2 y19d ff4 fs0 fc0 sc0 ls68 wsa5">(c) O p<span class="blank _5"> </span>otencial no in<span class="blank _0"></span>terior do tubo deve ser solu¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao da Eq.</div><div class="t m0 x0 h2 y19e ff4 fs0 fc0 sc0 ls68 wsa6">de Laplace, uma vez que <span class="ff2 lsd3">ρ</span>=<span class="blank _1d"> </span>0.<span class="blank _23"> </span>Se utilizarmos o m´<span class="blank _6"></span>eto<span class="blank _5"> </span>do</div><div class="t m0 x0 h2 y19f ff4 fs0 fc0 sc0 ls68 wsa7">de separa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao de v<span class="blank _0"></span>ari´<span class="blank _8"></span>aveis em coordenadas cartesianas,<span class="blank _4"> </span>o</div><div class="t m0 x0 h2 y1a0 ff4 fs0 fc0 sc0 ls68 wsa8">p<span class="blank _5"> </span>otencial el<span class="blank _0"></span>´<span class="blank _6"></span>etrico toma a forma discutida no problema an-</div><div class="t m0 x0 h2 y1a1 ff4 fs0 fc0 sc0 ls68 wsa9">terior, <span class="ff2 ls2f">V</span><span class="wsf">(<span class="ff2 ws19">x,<span class="blank _c"> </span>y </span><span class="ws2a">) = <span class="ff2 ls83">X</span><span class="ls16">(<span class="ff2 ls11">x</span></span></span>)<span class="ff2 ls84">Y</span>(<span class="ff2 ls14">y</span><span class="ws7">), com</span></span></div><div class="t m0 x0 h3d y1a2 fff fs3 fc0 sc0 lsd4">X<span class="ff10 lsd5">(</span><span class="ls68 ws9a">x<span class="ff10 wsaa">) = </span>A<span class="ff14 fs4 lsd6 v23">x</span><span class="lsd7">e</span><span class="ff11 fs4 wsab v12">+<span class="ff14">k<span class="ffc fs2 ls89 v23">x</span><span class="lsd8">x</span></span></span><span class="ff10 lsd9">+</span>B<span class="ff14 fs4 lsd6 v23">x</span><span class="lsd7">e</span><span class="ff15 fs4 wsab v12">−<span class="ff14">k<span class="ffc fs2 ls89 v23">x</span><span class="lsda">x</span></span></span><span class="ff10 lsdb">e</span><span class="lsdc">Y<span class="ff10 lsd5">(</span><span class="lsdd">y</span></span><span class="ff10 wsaa">) = </span>A<span class="ff14 fs4 lsde v23">y</span><span class="lsd7">e</span><span class="ff11 fs4 wsab v12">+<span class="ff14">k<span class="ffc fs2 ls8f v23">y</span><span class="lsdf">y</span></span></span><span class="ff10 lsd9">+</span><span class="lse0">B<span class="ff14 fs4 lsde v23">y</span></span>e<span class="ff15 fs4 wsab v12">−<span class="ff14 lse1">k<span class="ffc fs2 ls8f v23">y</span><span class="lsde">y</span></span></span>,</span></div><div class="t m0 x3f h1f y1a3 ff4 fs0 fc0 sc0 ls68 wsac">para qualquer <span class="ff2 ls95">k<span class="ff9 fs1 lse2 v1">x</span></span><span class="lse3">e<span class="ff2 ls95">k<span class="ff9 fs1 lsb7 v1">y</span></span></span><span class="wsad">, desde que <span class="ff2 ls97">k</span><span class="ff3 fs1 ve">2</span></span></div><div class="t m0 x1c h28 y1a4 ff9 fs1 fc0 sc0 lse4">x<span class="ff4 fs0 lse5 v22">+<span class="ff2 ls97">k</span></span><span class="ff3 ls68 v13">2</span></div><div class="t m0 x25 h29 y1a4 ff9 fs1 fc0 sc0 ls99">y<span class="ff4 fs0 ls68 wsc v22">= 0.<span class="blank _a"> </span><span class="ff2 ls86">A</span></span><span class="ls68 wsae v2d">x,y </span><span class="ff4 fs0 lse3 v22">e<span class="ff2 ls8b">B</span></span><span class="ls68 v2d">x,y</span></div><div class="t m0 x0 h2 y1a5 ff4 fs0 fc0 sc0 ls68 wsaf">s˜<span class="blank _8"></span>ao as constantes arbrit´<span class="blank _8"></span>arias.<span class="blank _21"> </span>Como a Eq.<span class="blank _16"> </span>de Laplace<span class="blank _18"> </span>´<span class="blank _2"></span>e</div><div class="t m0 x0 h2 y1a6 ff4 fs0 fc0 sc0 ls68 wsb0">linear em <span class="ff2 ls2f">V</span>, a solu¸<span class="blank _2"></span>c˜<span class="blank _6"></span>ao geral ´<span class="blank _8"></span>e a combina¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao linear destas</div><div class="t m0 x0 h2 y1a7 ff4 fs0 fc0 sc0 ls68 ws7">infinitas solu¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes, ou seja,</div><div class="t m0 x0 h3e y1a8 fff fs3 fc0 sc0 lse6">V<span class="ff10 lsd5">(</span><span class="ls68 wsb1">x,<span class="blank _c"> </span>y<span class="ff10 wsb2">) =<span class="blank _4"> </span><span class="ffa fs0 v25">X</span></span></span></div><div class="t m0 x8f h3f y1a9 ff14 fs4 fc0 sc0 lse1">k<span class="ffc fs2 ls89 v23">x</span><span class="ls68 wsab">,k<span class="ffc fs2 v23">y</span></span></div><div class="t m0 x11 h3d y1a8 ff10 fs3 fc0 sc0 lsd5">(<span class="fff ls68 ws9a">A<span class="ff14 fs4 lse1 v23">k</span><span class="ffc fs2 lse7 vd">x</span><span class="lsd7">e</span><span class="ff11 fs4 wsab v12">+<span class="ff14">k<span class="ffc fs2 ls89 v23">x</span><span class="lsd8">x</span></span></span></span><span class="lsd9">+<span class="fff ls68 ws9a">B<span class="ff14 fs4 lse1 v23">k</span><span class="ffc fs2 lse8 vd">x</span>e<span class="ff15 fs4 wsab v12">−<span class="ff14 lse1">k<span class="ffc fs2 ls8d v23">x</span><span class="lsd6">x</span></span></span><span class="ff10">)(</span>A<span class="ff14 fs4 wsab v23">k</span><span class="ffc fs2 lse9 vd">y</span>e<span class="ff11 fs4 wsab v12">+<span class="ff14">k<span class="ffc fs2 ls8f v23">y</span><span class="lsdf">y</span></span></span></span><span class="lsea">+<span class="fff ls68 ws9a">B<span class="ff14 fs4 wsab v23">k</span><span class="ffc fs2 lseb vd">y</span><span class="lsd7">e</span><span class="ff15 fs4 wsab v12">−<span class="ff14">k<span class="ffc fs2 ls8f v23">y</span><span class="lsde">y</span></span></span></span></span></span>)<span class="fff ls68">.</span></div><div class="t m0 x3f h2 y1aa ff4 fs0 fc0 sc0 ls68 ws13">Aplicando a condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao de contorno (1), temos</div><div class="t m0 x0 h40 y1ab ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 wsb3">x, <span class="ff4 wsc">0) =<span class="blank _26"> </span><span class="ffa v2e">X</span></span></span></div><div class="t m0 x1 h41 y1ac ff9 fs1 fc0 sc0 ls68 ws23">k<span class="ffc fs2 ls89 v23">x</span>,k<span class="ffc fs2 lsec v23">y</span><span class="ffa fs0 lsed v2f"><span class="ff2 ls86 v30">A</span></span><span class="v28">k</span><span class="ffc fs2 lse8 v2e">x</span><span class="ff2 fs0 ls88 v31">e</span><span class="ff3 ws1b v26">+</span><span class="v26">k</span><span class="ffc fs2 ls89 v1e">x</span><span class="ls98 v26">x</span><span class="ff4 fs0 ls26 v31">+<span class="ff2 ls8b">B</span></span><span class="v28">k</span><span class="ffc fs2 lse8 v2e">x</span><span class="ff2 fs0 ls88 v31">e</span><span class="ffb lsc8 v26">−</span><span class="v26">k</span><span class="ffc fs2 ls89 v1e">x</span><span class="ls87 v26">x</span><span class="ffa fs0 wsb4 v2f"> <span class="ff2 ls86 v30">A</span></span><span class="v28">k</span><span class="ffc fs2 lsee v2e">y</span><span class="ff4 fs0 ls13 v31">+<span class="ff2 ls68 ws1a">B</span></span><span class="ls8c v28">k</span><span class="ffc fs2 lseb v2e">y</span><span class="ffa fs0 lsef v2f"></span><span class="ff4 fs0 wsc v31">= 0<span class="ff2">.</span></span></div><div class="t m0 x0 h2 y1ad ff4 fs0 fc0 sc0 ls68 wsb5">P<span class="blank _0"></span>ara que esta igualdade seja satisfeita,<span class="blank _20"> </span>para qualquer <span class="ff2 ls11">x</span>,</div><div class="t m0 x0 h2 y1ae ff4 fs0 fc0 sc0 ls68 wsb6">en<span class="blank _0"></span>t˜<span class="blank _8"></span>ao <span class="ff2 ls86">A</span><span class="ff9 fs1 ws23 v1">k</span><span class="ffc fs2 lsf0 vd">y</span><span class="lsb">=<span class="ff8 lsc">−</span></span><span class="ff2 ws1a">B<span class="ff9 fs1 ls8c v1">k</span><span class="ffc fs2 lseb vd">y</span></span><span class="ws13">, de mo<span class="blank _5"> </span>do que <span class="ff2 ls2f">V</span><span class="ls16">(</span><span class="ff2 ws6b">x,<span class="blank _c"> </span>y </span><span class="ws7">) toma a forma</span></span></div><div class="t m0 x0 h42 y1af ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws19">x,<span class="blank _c"> </span>y <span class="ff4 wsc">) =<span class="blank _26"> </span><span class="ffa v2e">X</span></span></span></div><div class="t m0 x1 h17 y1b0 ff9 fs1 fc0 sc0 ls68 ws23">k<span class="ffc fs2 ls89 v23">x</span>,k<span class="ffc fs2 v23">y</span></div><div class="t m0 x87 hc y1af ff2 fs0 fc0 sc0 ls86">A<span class="ff9 fs1 ls8c v1">k</span><span class="ffc fs2 lsf1 vd">y</span><span class="ffa lsf2 v32"></span>A<span class="ff9 fs1 ls68 ws23 v1">k</span><span class="ffc fs2 lse8 vd">x</span><span class="ls88">e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 ws23">k<span class="ffc fs2 ls89 v23">x</span><span class="ls8a">x</span></span></span><span class="ff4 ls13">+</span><span class="ls8b">B<span class="ff9 fs1 ls68 ws23 v1">k</span><span class="ffc fs2 lse8 vd">x</span></span>e<span class="ffb fs1 ls68 ws2f v12">−<span class="ff9 ls8c">k<span class="ffc fs2 ls8d v23">x</span><span class="ls87">x</span></span></span><span class="ffa ls68 wsb4 v32"> </span>e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="ls90">y</span></span></span><span class="ff8 ls13">−</span>e<span class="ffb fs1 ls68 ws2f v12">−<span class="ff9 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="ls8e">y</span></span></span><span class="ffa lsf3 v32"></span><span class="ls68">.</span></span></div><div class="t m0 x0 h2 y1b1 ff4 fs0 fc0 sc0 ls68 ws18">Incorp orando<span class="blank _23"> </span><span class="ff2 ls86">A</span><span class="ff9 fs1 ws23 v1">k</span><span class="ffc fs2 lsf4 vd">y</span><span class="wsb7">`<span class="blank _6"></span>as outras constantes,<span class="blank _25"> </span>e aplicando a</span></div><div class="t m0 x0 h2 y1b2 ff4 fs0 fc0 sc0 ls68 ws7">condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao de contorno (2), temos</div><div class="t m0 x0 h42 y1b3 ff2 fs0 fc0 sc0 ls8">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws30">x, a<span class="ff4 wsc">) =<span class="blank _26"> </span><span class="ffa v2e">X</span></span></span></div><div class="t m0 x1 h41 y1b4 ff9 fs1 fc0 sc0 ls68 ws23">k<span class="ffc fs2 ls89 v23">x</span>,k<span class="ffc fs2 lsec v23">y</span><span class="ffa fs0 lsed v2f"><span class="ff2 ls86 v30">A</span></span><span class="v28">k</span><span class="ffc fs2 lse8 v2e">x</span><span class="ff2 fs0 ls88 v31">e</span><span class="ff3 ws1b v26">+</span><span class="v26">k</span><span class="ffc fs2 ls89 v1e">x</span><span class="ls98 v26">x</span><span class="ff4 fs0 ls26 v31">+<span class="ff2 ls8b">B</span></span><span class="v28">k</span><span class="ffc fs2 lse8 v2e">x</span><span class="ff2 fs0 ls88 v31">e</span><span class="ffb lsc8 v26">−</span><span class="v26">k</span><span class="ffc fs2 ls89 v1e">x</span><span class="ls87 v26">x</span><span class="ffa fs0 wsb4 v2f"> <span class="ff2 ws1a v30">e</span></span><span class="ff3 ws1b v26">+</span><span class="ls8c v26">k</span><span class="ffc fs2 ls8f v1e">y</span><span class="lsf5 v26">a</span><span class="ff8 fs0 ls13 v31">−<span class="ff2 ls88">e</span></span><span class="ffb ws2f v26">−</span><span class="ls8c v26">k</span><span class="ffc fs2 ls8f v1e">y</span><span class="lsf6 v26">a</span><span class="ffa fs0 lsf7 v2f"></span><span class="ff4 fs0 wsc v31">= 0<span class="ff2">,</span></span></div><div class="t m0 x43 h1f y1 ff4 fs0 fc0 sc0 ls68 wsb8">que<span class="blank _2b"> </span>´<span class="blank _6"></span>e satisfeita quando <span class="ff2 ls88">e</span><span class="ff3 fs1 ws1b ve">+<span class="ff9 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="lsf8">a</span></span></span><span class="ff8 lsf9">−<span class="ff2 ls88">e<span class="ffb fs1 lsc8 ve">−<span class="ff9 ls68 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="lsfa">a</span></span></span></span></span><span class="wsb9">=<span class="blank _10"> </span>0.<span class="blank _18"> </span>A escolha <span class="ff2 ls95">k<span class="ff9 fs1 ls99 v1">y</span></span><span class="wsc">= 0,</span></span></div><div class="t m0 x43 h2 y2 ff4 fs0 fc0 sc0 ls68 wsba">que satisfaz esta equa¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao,<span class="blank _26"> </span>implicaria n<span class="blank _0"></span>uma forma trivial</div><div class="t m0 x43 h2 y3 ff4 fs0 fc0 sc0 ls68 wsbb">para <span class="ff2 lsa7">Y</span><span class="ls16">(<span class="ff2 ls14">y</span></span><span class="ws9d">).<span class="blank _1c"> </span>A igualdade po<span class="blank _5"> </span>de ser resp<span class="blank _5"> </span>eitada de maneira</span></div><div class="t m0 x43 h2 ya7 ff4 fs0 fc0 sc0 ls68 wsbc">n˜<span class="blank _8"></span>ao-trivial se admitirmos <span class="ff2 ws1a">k<span class="ff9 fs1 lsfb v1">y</span></span>como um n<span class="blank _5"> </span>´<span class="blank _8"></span>umero imagin´<span class="blank _8"></span>ario</div><div class="t m0 x43 h43 ya8 ff4 fs0 fc0 sc0 ls68 wsbd">puro <span class="ff2 ws1a">k<span class="ff9 fs1 ls99 v1">y</span></span><span class="lsb">=<span class="ff2 lsfc">i</span></span><span class="v22">¯</span></div><div class="t m0 x80 h2 ya8 ff2 fs0 fc0 sc0 ls68 ws1a">k<span class="ff9 fs1 ls8e v1">y</span><span class="ff4 ws13">, de mo<span class="blank _5"> </span>do que</span></div><div class="t m0 x66 h43 y1b5 ff2 fs0 fc0 sc0 ls88">e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="lsfd">a</span></span></span><span class="ff8 ls13">−</span><span class="ls68 ws1a">e<span class="ffb fs1 lsc8 v12">−<span class="ff9 ls68 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="lsfa">a</span></span></span><span class="ff4 wsc">= 0<span class="blank _2c"> </span>=<span class="blank _22"></span><span class="ff8 lsfe">⇒<span class="ff4 ls68 wsf">2<span class="ff2 lsff">i</span><span class="wsbe">sin(<span class="v22">¯</span></span></span></span></span></span></div><div class="t m0 x4b h2 y1b5 ff2 fs0 fc0 sc0 ls95">k<span class="ff9 fs1 lsb7 v1">y</span><span class="ls68 ws1a">a</span><span class="ff4 lsa3 ws7f">)=0<span class="blank _24"></span><span class="ff2 ls68">.</span></span></div><div class="t m0 x43 h2 y1b6 ff4 fs0 fc0 sc0 ls68 wsbf">A restri¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao agora restringe a constante inicialmen<span class="blank _0"></span>te ar-</div><div class="t m0 x43 h43 y1b7 ff4 fs0 fc0 sc0 ls68 wsc0">bitr´<span class="blank _8"></span>aria para<span class="blank _4"> </span><span class="v22">¯</span></div><div class="t m0 x81 h2 y1b7 ff2 fs0 fc0 sc0 ls95">k<span class="ff9 fs1 ls8e v1">y</span><span class="ls100">a<span class="ff4 ls101">=</span><span class="ls68 wsc1">nπ <span class="ff4 wsc2">,<span class="blank _4"> </span>com </span><span class="ls102">n</span><span class="ff4 wsc3">= 0</span><span class="ls1a">,</span><span class="ff8 wsb">±<span class="ff4 ls38">1</span></span><span class="ls103">,<span class="ff8 lsc">±</span></span><span class="ff4 wsf">2</span><span class="ws30">, . . .<span class="ff4 wsc4">. Sendo</span></span></span></span></div><div class="t m0 x43 h2 y1b8 ff4 fs0 fc0 sc0 ls68 wsc5">assim, <span class="ff2 ls8">V</span><span class="wsf">(<span class="ff2 ws19">x,<span class="blank _c"> </span>y </span><span class="ws7">) toma a forma</span></span></div><div class="t m0 x43 h40 y1b9 ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls68 wsf">(</span><span class="ls68 ws19">x,<span class="blank _c"> </span>y <span class="ff4 wsc6">) =<span class="blank _2c"> </span><span class="ffa v2e">X</span></span></span></div><div class="t m0 x90 h44 y1ba ff9 fs1 fc0 sc0 ls68 ws23">k<span class="ffc fs2 ls89 v23">x</span><span class="ls104">,</span><span class="ff3 v33">¯</span></div><div class="t m0 x4f h45 y1ba ff9 fs1 fc0 sc0 ls68 ws23">k<span class="ffc fs2 ls105 v23">y</span><span class="ffa fs0 lsf2 vf"><span class="ff2 ls86 v30">A</span></span><span class="v34">k</span><span class="ffc fs2 lse8 v28">x</span><span class="ff2 fs0 ls88 v15">e</span><span class="ff3 ws1b v11">+</span><span class="v11">k</span><span class="ffc fs2 ls89 v26">x</span><span class="ls98 v11">x</span><span class="ff4 fs0 ls26 v15">+<span class="ff2 ls8b">B</span></span><span class="v34">k</span><span class="ffc fs2 lse8 v28">x</span><span class="ff2 fs0 ls88 v15">e</span><span class="ffb lsc8 v11">−</span><span class="v11">k</span><span class="ffc fs2 ls89 v26">x</span><span class="ls87 v11">x</span><span class="ffa fs0 ls106 vf"><span class="ls107 vb"><span class="ff2 ls88 v35">e</span></span></span><span class="ff3 ws1b v11">+</span><span class="ls108 v11">i</span><span class="ff3 v36">¯</span></div><div class="t m0 x7e h44 y1bb ff9 fs1 fc0 sc0 ls68 ws23">k<span class="ffc fs2 ls8f v23">y</span><span class="ls90">y<span class="ff8 fs0 ls26 v2">−<span class="ff2 ls88">e</span></span><span class="ffb lsc8">−</span><span class="ls108">i</span></span><span class="ff3 v33">¯</span></div><div class="t m0 x91 h46 y1bb ff9 fs1 fc0 sc0 ls8c">k<span class="ffc fs2 ls8f v23">y</span><span class="ls8e">y<span class="ffa fs0 ls68 va"></span></span></div><div class="t m0 x72 h2 y1bc ff4 fs0 fc0 sc0 ls68">=</div><div class="t m0 x81 h47 y1bd ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x90 h14 y1be ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x90 h17 y1bf ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68">=1</span></div><div class="t m0 x92 h6 y1bc ff4 fs0 fc0 sc0 ls38">2<span class="ff2 ls10a">i<span class="ffa ls107 v21"></span><span class="ls86">A<span class="ff9 fs1 ls10b v1">n</span><span class="ls88">e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 wsc7">nπ x/a<span class="blank _1e"> </span></span></span></span></span></span><span class="ls13">+<span class="ff2 ls68 ws1a">B<span class="ff9 fs1 ls10b v1">n</span><span class="ls88">e<span class="ffb fs1 lsc8 v12">−<span class="ff9 ls68 wsc7">nπ x/a<span class="blank _5"> </span></span></span><span class="ffa ls10c v21"></span></span></span><span class="ls68 wsc8">sin <span class="ffa ls10d v21"></span><span class="ff2 va">nπ</span></span></span></div><div class="t m0 x93 h48 y1c0 ff2 fs0 fc0 sc0 ls10e">a<span class="ls14 va">y</span><span class="ffa ls10c v20"></span><span class="ls68 va">.</span></div><div class="t m0 x43 h2 y1c1 ff4 fs0 fc0 sc0 ls68 wsc9">Aqui,<span class="blank _17"> </span>excluimos o termo com <span class="ff2 ls10f">n</span>=<span class="blank _17"> </span>0 p<span class="blank _5"> </span>ois gera uma con-</div><div class="t m0 x43 h2 y1c2 ff4 fs0 fc0 sc0 ls68 wsca">tribui¸<span class="blank _2"></span>c˜<span class="blank _8"></span>ao nula, e tamb<span class="blank _0"></span>´<span class="blank _6"></span>em aqueles em que <span class="ff2 wscb">n < </span><span class="ws29">0,<span class="blank _20"> </span>porque</span></div><div class="t m0 x43 h2 y1c3 ff4 fs0 fc0 sc0 ls68 wscc">implicaria ap<span class="blank _5"> </span>enas em fator n<span class="blank _0"></span>um<span class="blank _0"></span>´<span class="blank _6"></span>erico <span class="ff8 lsc">−</span><span class="ws29">1,<span class="blank _18"> </span>incorp orado<span class="blank _18"> </span>nas</span></div><div class="t m0 x43 h24 y1c4 ff4 fs0 fc0 sc0 ls68 wsa0">constan<span class="blank _0"></span>tes arbitr´<span class="blank _8"></span>arias.<span class="blank _1c"> </span>J´<span class="blank _6"></span>a usamos tamb<span class="blank _3"></span>´<span class="blank _2"></span>em <span class="ff2 ls97">k</span><span class="ff3 fs1 ve">2</span></div><div class="t m0 x94 h49 y1c5 ff9 fs1 fc0 sc0 ls110">x<span class="ff4 fs0 ls111 v22">=<span class="ff8 lsc">−<span class="ff2 ls97">k</span></span></span><span class="ff3 ls68 v13">2</span></div><div class="t m0 x95 h29 y1c5 ff9 fs1 fc0 sc0 ls112">y<span class="ff4 fs0 ls68 v22">=</span></div><div class="t m0 x43 h2 y1c6 ff4 fs0 fc0 sc0 ls68">¯</div><div class="t m0 x43 h1f y1c7 ff2 fs0 fc0 sc0 ls97">k<span class="ff3 fs1 ls68 ve">2</span></div><div class="t m0 x96 h28 y1c8 ff9 fs1 fc0 sc0 ls113">y<span class="ff4 fs0 ls68 wscd v22">= (<span class="ff2 ws10">nπ /a<span class="ff4 wsf">)</span></span></span><span class="ff3 ls5a v13">2</span><span class="ff4 fs0 ls68 wsce v22">.<span class="blank _2a"> </span>Incorporando o fator 2<span class="ff2 ls114">i</span>nas constantes</span></div><div class="t m0 x43 h2 y1c9 ff4 fs0 fc0 sc0 ls68 wscf">arbitr´<span class="blank _8"></span>arias remanescentes, aplicamos as condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes de con-</div><div class="t m0 x43 h2 y1ca ff4 fs0 fc0 sc0 ls68 ws7">torno (3) e (4), temos</div><div class="t m0 x43 h2 y1cb ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls68 wsf">(<span class="ff8 lsc">−</span></span><span class="ls68 wsa2">b,<span class="blank _c"> </span>y <span class="ff4 wsc">) =</span></span></div><div class="t m0 x4d h47 y1cc ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x74 h14 y1cd ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x97 h4a y1ce ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68 wsd0">=1 <span class="ffa fs0 ls107 v37"><span class="ff2 ls86 v35">A</span></span></span><span class="ls10b v28">n</span><span class="ff2 fs0 ls88 v34">e</span><span class="ffb ls68 ws2f v38">−</span><span class="ls68 wsc7 v38">nπ b/a<span class="blank _1e"> </span></span><span class="ff4 fs0 ls13 v34">+<span class="ff2 ls68 ws1a">B</span></span><span class="ls10b v28">n</span><span class="ff2 fs0 ls88 v34">e</span><span class="ff3 ls68 ws1b v38">+</span><span class="ls68 wsc7 v38">nπ b/a<span class="blank _5"> </span></span><span class="ffa fs0 ls10c v37"><span class="ff4 ls68 wsc8 v35">sin </span><span class="ls10d"><span class="ff2 ls68 v39">nπ</span></span></span></div><div class="t m0 x98 h48 y1cf ff2 fs0 fc0 sc0 ls10e">a<span class="ls14 va">y</span><span class="ffa ls115 v20"></span><span class="ff4 lsb va">=</span><span class="ls76 va">V</span><span class="ff3 fs1 ls15 v27">0</span><span class="ls68 va">,</span></div><div class="t m0 x99 h2 y1d0 ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls68 wsf">(+</span><span class="ls68 wsd1">b,<span class="blank _c"> </span>y <span class="ff4 wsc">) =</span></span></div><div class="t m0 x4e h47 y1d1 ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x74 h14 y1d2 ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x74 h4a y1d3 ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68 wsd2">=1 <span class="ffa fs0 ls107 v37"><span class="ff2 ls86 v35">A</span></span></span><span class="ls10b v28">n</span><span class="ff2 fs0 ls88 v34">e</span><span class="ff3 ls68 ws1b v38">+</span><span class="ls68 wsc7 v38">nπ b/a<span class="blank _1e"> </span></span><span class="ff4 fs0 ls26 v34">+<span class="ff2 ls8b">B</span></span><span class="ls10b v28">n</span><span class="ff2 fs0 ls88 v34">e</span><span class="ffb lsc8 v38">−</span><span class="ls68 wsc7 v38">nπ b/a<span class="blank _5"> </span></span><span class="ffa fs0 ls10c v37"><span class="ff4 ls68 wsd3 v35">sin </span><span class="ls116"><span class="ff2 ls68 v39">nπ</span></span></span></div><div class="t m0 x9a h4b y1d4 ff2 fs0 fc0 sc0 ls10e">a<span class="ls5e va">y</span><span class="ffa ls117 v20"></span><span class="ff4 lsb va">=</span><span class="ls68 ws1a va">V</span><span class="ff3 fs1 ls5a v27">0</span><span class="ls68 va">,</span></div><div class="t m0 x43 h2 y1d5 ff4 fs0 fc0 sc0 ls68 ws7">que s˜<span class="blank _8"></span>ao simultaneamen<span class="blank _3"></span>te<span class="blank _d"> </span>satisfeitas quando</div><div class="t m0 x96 hc y1d6 ff2 fs0 fc0 sc0 ls86">A<span class="ff9 fs1 ls10b v1">n</span><span class="ls88">e<span class="ffb fs1 ls68 ws2f v12">−<span class="ff9 wsc7">nπ b/a<span class="blank _1e"> </span></span></span><span class="ff4 ls13">+</span><span class="ls8b">B<span class="ff9 fs1 ls10b v1">n</span><span class="ls68 ws1a">e<span class="ff3 fs1 ws1b v12">+<span class="ff9 wsc7">nπ b/a<span class="blank _1d"> </span></span></span><span class="ff4 lsb">=</span></span></span></span>A<span class="ff9 fs1 ls10b v1">n</span><span class="ls88">e<span class="ff3 fs1 ls68 ws1b v12">+<span class="ff9 wsc7">nπb/a<span class="blank _10"> </span></span></span><span class="ff4 ls13">+</span><span class="ls8b">B<span class="ff9 fs1 ls10b v1">n</span></span>e<span class="ffb fs1 ls68 ws2f v12">−<span class="ff9 wsc7">nπb/a<span class="blank _1b"> </span></span></span><span class="ls68">,</span></span></div><div class="t m0 x43 h2 y1d7 ff4 fs0 fc0 sc0 ls68 wsd4">o que pro<span class="blank _5"> </span>duz <span class="ff2 ls86">A<span class="ff9 fs1 ls118 v1">n</span></span><span class="ls119">=</span><span class="ff2 ws1a">B<span class="ff9 fs1 ls10b v1">n</span></span>.<span class="blank _a"> </span>Sendo assim, <span class="ff2 ls2f">V</span><span class="wsf">(<span class="ff2 ws19">x,<span class="blank _c"> </span>y </span></span>) toma a forma</div><div class="t m0 x9b h2 y1d8 ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls16">(</span><span class="ls68 ws6b">x,<span class="blank _c"> </span>y <span class="ff4 wsc6">) =</span></span></div><div class="t m0 x9c h47 y1d9 ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x9d h14 y1da ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x9d h17 y1db ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68">=1</span></div><div class="t m0 x70 h10 y1d8 ff2 fs0 fc0 sc0 ls86">A<span class="ff9 fs1 ls11a v1">n</span><span class="ffa ls107 v21"></span><span class="ls68 ws1a">e<span class="ff3 fs1 ws1b v12">+<span class="ff9 wsc7">nπ x/a<span class="blank _1e"> </span></span></span><span class="ff4 ls13">+</span><span class="ls88">e<span class="ffb fs1 lsc8 v12">−<span class="ff9 ls68 wsc7">nπ x/a<span class="blank _5"> </span></span></span><span class="ffa ls10c v21"></span></span><span class="ff4 wsd3">sin <span class="ffa ls116 v21"></span></span><span class="va">nπ</span></span></div><div class="t m0 x9e h48 y1dc ff2 fs0 fc0 sc0 ls10e">a<span class="ls14 va">y</span><span class="ffa ls68 v20"></span></div><div class="t m0 x74 h2 y1dd ff4 fs0 fc0 sc0 ls68">=</div><div class="t m0 x9c h47 y1de ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x9d h14 y1df ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x9d h17 y1e0 ff9 fs1 fc0 sc0 ls68 ws23">n<span class="ff3">=1</span></div><div class="t m0 x70 h6 y1dd ff4 fs0 fc0 sc0 ls68 wsf">2<span class="ff2 ls86">A<span class="ff9 fs1 ls11a v1">n</span></span><span class="ws99">cosh <span class="ffa ls10d v21"></span><span class="ff2 va">nπ</span></span></div><div class="t m0 x60 h26 y1e1 ff2 fs0 fc0 sc0 ls10e">a<span class="ls11 va">x</span><span class="ffa ls10c v20"></span><span class="ff4 ls68 wsc8 va">sin </span><span class="ffa ls10d v20"></span><span class="ls68 v10">nπ</span></div><div class="t m0 x9f h4b y1e1 ff2 fs0 fc0 sc0 ls10e">a<span class="ls14 va">y</span><span class="ffa ls10c v20"></span><span class="ls68 va">.</span></div><div class="t m0 x43 h2 y1e2 ff4 fs0 fc0 sc0 ls68 wsd5">V<span class="blank _f"></span>oltando agora `<span class="blank _6"></span>as condi¸<span class="blank _2"></span>c˜<span class="blank _8"></span>oes de contorno (3) e (4), e incor-</div><div class="t m0 x43 h2 y1e3 ff4 fs0 fc0 sc0 ls68 ws7">p<span class="blank _5"> </span>orando o fator 2 aos <span class="ff2 ls86">A<span class="ff9 fs1 ls10b v1">n</span></span>’s, conclui-se que am<span class="blank _0"></span>bas s˜<span class="blank _8"></span>ao</div><div class="t m0 xa0 h2 y1e4 ff2 fs0 fc0 sc0 ls2f">V<span class="ff4 ls68 wsf">(<span class="ff8 lsc">±</span></span><span class="ls68 wsa2">b,<span class="blank _c"> </span>y <span class="ff4 wsc">) =</span></span></div><div class="t m0 x75 h47 y1e5 ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x82 h14 y1e6 ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x82 h17 y1e7 ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68">=1</span></div><div class="t m0 xa1 h4c y1e4 ff2 fs0 fc0 sc0 ls86">A<span class="ff9 fs1 ls11b v1">n</span><span class="ff4 ls68 ws99">cosh <span class="ffa ls11c v3a"></span></span><span class="ls68 ws10 va">nπ b</span></div><div class="t m0 x5f h11 y1e8 ff2 fs0 fc0 sc0 ls11d">a<span class="ffa ls11e vf"></span><span class="ff4 ls68 wsd3 va">sin </span><span class="ffa ls116 v20"></span><span class="ls68 v10">nπ</span></div><div class="t m0 xa2 h4b y1e8 ff2 fs0 fc0 sc0 ls10e">a<span class="ls14 va">y</span><span class="ffa ls115 v20"></span><span class="ff4 lsb va">=</span><span class="ls68 ws1a va">V<span class="ff3 fs1 v1">0</span></span></div><div class="t m0 x43 h2 y1e9 ff4 fs0 fc0 sc0 ls68 wsd6">Multiplicando p<span class="blank _5"> </span>or sin(<span class="ff2 ws10">mπ y /a</span>) e in<span class="blank _0"></span>tegrando de 0 at<span class="blank _0"></span>´<span class="blank _6"></span>e <span class="ff2">a</span></div><div class="t m0 x43 h2 y1ea ff4 fs0 fc0 sc0 ls68">temos</div><div class="t m0 x63 h47 y1eb ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x79 h14 y1ec ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x79 h17 y1ed ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68">=1</span></div><div class="t m0 x7a h4d y1ee ff2 fs0 fc0 sc0 ls86">A<span class="ff9 fs1 ls11b v1">n</span><span class="ff4 ls68 ws99">cosh <span class="ffa ls11c v3a"></span></span><span class="ls68 ws10 va">nπ b</span></div><div class="t m0 x84 h20 y1ef ff2 fs0 fc0 sc0 ls11d">a<span class="ffa ls11e vf"><span class="ls11f v29">Z</span></span><span class="ff9 fs1 ls68 v20">a</span></div><div class="t m0 xa3 h17 y1f0 ff3 fs1 fc0 sc0 ls68">0</div><div class="t m0 xa4 h6 y1ee ff4 fs0 fc0 sc0 ls68 wsc8">sin <span class="ffa ls10d v21"></span><span class="ff2 va">nπ</span></div><div class="t m0 x4a h26 y1ef ff2 fs0 fc0 sc0 ls10e">a<span class="ls14 va">y</span><span class="ffa ls10c v20"></span><span class="ff4 ls68 wsc8 va">sin </span><span class="ffa ls10d v20"></span><span class="ls68 v10">mπ</span></div><div class="t m0 xa5 h4b y1ef ff2 fs0 fc0 sc0 ls120">a<span class="ls14 va">y</span><span class="ffa ls10c v20"></span><span class="ls68 va">dy</span></div><div class="t m0 x79 h4e y1f1 ff4 fs0 fc0 sc0 lsb">=<span class="ff2 ls76">V<span class="ff3 fs1 ls121 v1">0</span><span class="ffa ls6c v10">Z</span><span class="ff9 fs1 ls68 v21">a</span></span></div><div class="t m0 xa6 h17 y1f2 ff3 fs1 fc0 sc0 ls68">0</div><div class="t m0 x9d h6 y1f1 ff4 fs0 fc0 sc0 ls68 wsd3">sin <span class="ffa ls116 v21"></span><span class="ff2 va">mπ</span></div><div class="t m0 x64 h26 y1f3 ff2 fs0 fc0 sc0 ls120">a<span class="ls14 va">y</span><span class="ffa ls10c v20"></span><span class="ls68 wsd7 va">dy <span class="ff4 lsb">=<span class="ff8 ls4f">−</span></span></span><span class="ls68 ws1a v10">aV<span class="ff3 fs1 v1">0</span></span></div><div class="t m0 x7c h5 y1f3 ff2 fs0 fc0 sc0 ls68 wsd8">mπ <span class="ff4 wsd9 va">(cos </span><span class="wsda va">mπ <span class="ff8 ls13">−<span class="ff4 ls68 wsf">1)<span class="ff2">.</span></span></span></span></div><div class="t m0 x43 h2 y1f4 ff4 fs0 fc0 sc0 ls68 ws7">O lado esquerdo torna-se</div><div class="t m0 x63 h47 y1f5 ffb fs1 fc0 sc0 ls68">∞</div><div class="t m0 x79 h14 y1f6 ffa fs0 fc0 sc0 ls68">X</div><div class="t m0 x79 h17 y1f7 ff9 fs1 fc0 sc0 ls109">n<span class="ff3 ls68">=1</span></div><div class="t m0 x7a h4c y1f8 ff2 fs0 fc0 sc0 ls86">A<span class="ff9 fs1 ls11a v1">n</span><span class="ff4 ls68 ws99">cosh <span class="ffa ls11c v3a"></span></span><span class="ls68 ws10 va">nπ b</span></div><div class="t m0 x84 h11 y1f9 ff2 fs0 fc0 sc0 ls122">a<span class="ffa ls123 vf"></span><span class="ls68 v10">a</span></div><div class="t m0 x5e h5 y1f9 ff4 fs0 fc0 sc0 ls124">2<span class="ff2 lsc5 va">δ</span><span class="ff9 fs1 ls68 wsdb v27">mn </span><span class="lsb va">=<span class="ff2 ls86">A<span class="ff9 fs1 ls68 v1">m</span></span></span></div><div class="t m0 xa7 h2 y1fa ff2 fs0 fc0 sc0 ls68">a</div><div class="t m0 xa7 h11 y1f9 ff4 fs0 fc0 sc0 ls125">2<span class="ls68 ws99 va">cosh </span><span class="ffa ls11c vf"></span><span class="ff2 ls68 ws10 v10">mπ b</span></div><div class="t m0 xa8 h11 y1f9 ff2 fs0 fc0 sc0 ls126">a<span class="ffa ls11e vf"></span><span class="ls68 va">.</span></div><div class="t m0 x43 h4f y1fb ff4 fs0 fc0 sc0 ls68 wsdc">Assim,<span class="blank _4"> </span>encontra-se <span class="ff2 ls86">A<span class="ff9 fs1 ls127 v1">m</span></span><span class="ls128">=</span><span class="ff3 fs1 ws1b v12">2<span class="ff9 ls129">V</span></span><span class="ffd fs2 vb">0</span></div><div class="t m0 xa3 h17 y1fc ff9 fs1 fc0 sc0 ls68">mπ</div><div class="t m0 xa9 h17 y1fd ff3 fs1 fc0 sc0 ls68 ws1b">1<span class="ffb lsc8">−</span><span class="wsdd">cos <span class="ff9">mπ</span></span></div><div class="t m0 x60 h50 y1fe ff3 fs1 fc0 sc0 ls68 ws1b">cosh<span class="ff4 fs0 ls74 v23">(</span><span class="ffc fs2 wsde v22">mπb</span></div><div class="t m0 x7d h51 y1ff ffc fs2 fc0 sc0 ls12a">a<span class="ff4 fs0 ls74 v33">)<span class="ls68 wsdf v27">,<span class="blank _4"> </span>que repro<span class="blank _5"> </span>duz o</span></span></div><div class="t m0 x43 h2 ydc ff4 fs0 fc0 sc0 ls68 ws7">resultado mostrado.</div><div class="t m0 x85 h2 y13f ff4 fs0 fc0 sc0 ls68">3</div></div><div class="pi" data-data="{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}"></div></div>
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