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FUNCTIONS A. A function is a relation in wh ich each el ement of the d oma in (x value - independen t va ria bl e) is pa ired w ith only one e lement of the range (y value d epen de nt va riable). B. A re lation can be tested to see if it is a funct ion by the vertical line test. Draw a vertical line through any g raph, and if it hi t an x-value more than once, it is not a function . (1-4) b. b2 4ac = 0, exact ly one rea l r ot c. b2 - 4ac < 0, no real roots (two disti nct imaginary roots) I) Example l:f(x) =x2_4x+ I use -b ± /b 2 _ 4ac f( x)= 2a x = -(-4) + f< - 4 2 [!]E8rnrn A function Not a function Afunction A fu nction C. Linear funct ions take the form: f(x) = mx+b, or y = FE m x+b where m = the. lope, and b = the y-intercept. Example: f(x) = 4x-l , the s lope i 4/1 (ri e over run), and the y-intercept is -I. D. he dis tance between two points on a lin can be found u ing the distance form ula, d = j(X 2 - XI ) 2+ (Y2 - YI )2 X;~~5 E. The mid-point of a line segment can be found us ing the .. ( X2 + X I) (Y 2+ Vd ) m id-po lllt form ula, 2 • 2 ' . F. The s tandard form ofa linear function is 0 =Ax + By + C. The lope is m = -A/B, and the y-intercept is -C/B. G. The zeros of a funct ion a re found by setting y to O. and ffi No zeros solving for x. I. E xample .1: f(x) = 4x-1 (5) 2. Exam p le 2: f(x) = 6, this func tio n has no zero, and is a h ri z ntal line th rough +6 on the y-axi . (6) 3, Exam ple 3: x = 4, th i i not a function, because the re is a vertica l line through +4 on the x-axi , g ivi ng an in fi n ite set of va lues for y. (7) H. Polynomial function s take the form : f(x) = axn + bxn- I + cxn-2 ••• + d x + e I . When the highe t power o f the func ti on is an odd integer, there is at least one real zero. 2 . When the highe t power is an even integer, there may be no real zeros . EE3. Both type can have imaginary roots of the form a + bi. x=-1.170213 4. T h highest p wer of a po lynomi a l w ith one vari able is y=.0100806 called it degree. Example l: f(x) = 2x4 + x2 + X + 10, has a degree of tE 4, there are four roots (solutions) to th is polynomia l. 9 Example 2: f(x) = 2xJ + x2 - 2x + 3, thi function has one real zero at x = -1.17, and two non-real roots. (8) Example 3 : f(x) = x2 + I. this fUllction has'two non- real roots, (9) x=.10638298 l. Quadratic funct ions take the form : f(x) = ax2 + bx + c. y=1.0113173 I. 111e graph ofa quadrati function i called a parabola. (10) 2 . ome parabolas are quadrat ic eq uation , but onot tE q uadratic fu nctions. (II) 3. Quadratic functions or equat ions can have one real so lution. two rea l solutions, or no real solution. (12-14) 4 . Th vertex of a parabola i ca lled its critical p oint. - b ± jb2 - 4ac x=-1.010638 ). The quadratic equat ion f(x) = 2a can y=2.9737903 be u ed to f ind the roots of a ll quadratic eq uations. 6 . The a lue under th square root symbol is ca lled the d iscrim inan t. It te ll s u the type of roots o f a quadratic equat ion . a . b2 - 4ac > 0, t lVO dist inct rea l roots _ 4)/2 = 3.732, and x = -(-4) - f< - 4 - 4) /2 = .267. s ince the discriminant is > 0, there are two rea l roots. (15) 2) Example 2: f(x) = 2x2 + 2x + I us ing b2 - 4ac = -4, since the d iscriminant is < 0, there are two imaginary root . (16) 3) Example 3: f(x) = x2 + 2x + I us ing b2 - 4ac = 0, 1 d· .. . 0 th ' I 17since t le ISCnl11l11ant IS = ere IS one rea I' \. ( ) .. g(x) J . RatIOnal function s take the fori: f(x) = b (x) . I . The parent fu nction i f(x) = X · 2. The g raph of these functi ons cons ist of two pan s, one in quadrant I, and one in quadrant 3. 3. The bran hes of rational functi on approac h line called asymptotes. (18) x 4. Example I: f(x) = x + 3 (19) 3 5. Exam ple 2: f(x) = x (20) 6 . Example 3: f(x) = ~2 + 3 (21) x - K. Oper ations of fu nctions: I. Sum: (f + g)(x) = f(x) + g(x) 2. Difference: (f - g)(x) = f(x) - g(x) 3. P roduct: (f x g)(x) = f(x) x g(x) . (f) f(x) 4. QuotIent: g (x) = g (x )' g( x) f. 0 5. Example I: Given f(x) = x + 2, g (x) == x:. 4 a . Find the sum : (f + g)(x), x + 2 + ~ ( x + 2 ) (x - 4) + x X 2 _ X _ 8 x x - 4 = x - 4 ' and x f. 4. b. Find the di fference: (f - g)(x), x + 2 -~ (x + 2) (x - 4 ) - x x _ 3x _ 8 x x - 4 = x _ 4 • and x f. 4. 6. Example 2: Given f(x) = x + 2, g(x) = x:. 4 a. Find the product: (fxg)(x), (x + 2)( x :. 4 ) = x 2 + 2x ---x=-;t. an d x f. 4. b. Find the quot ient: ( t )(X), x;x+_24 = ( X - 4) x2 -2x - S(x+2) .-x- = x , andx f. O. L. c omP.osition of functions:lfog l(x) = f(g(x» E!J8 Example: Gi en f(x)=x+2, g(x)= :. 4 + 2. Find IfogJ(x): f ( x :. 4 + 2 ) = 2 ( 4 ) x-- 0265958( _ x_ + 2 ) + 2 = x + x - + 2 y~.OlO0806 x - 4 (x - 4) A rationalfunction with asymptotes5x - 16 at the x& y axes. , and x f. 4.4x- M .lnverse function s : Ifog l(x) = Igofj( x) OFE · +4 Example: Given f(x)=2x - 4, g(x) = ~, _ ('X+4)_ (X +4) _Ifog l(x) - f -2- - 2 -2- - 4 - x, x=.02659573( 2 4 ) 4X - + y=-.0100806 and I gO fj( x) = 2 = x. The asymptotes are the axes y=-.0100807 One real solullOn EE/3 x=1.2765957 y=-2. 1 06855 Two real solutions EE4 x=-.9574468 y=7.9737903 No real solutions EE x=1.3829787 y=-2.671371 Two real roots, (.26,0) &(3.73,0) ra x=-.5053192 y=.47379034 Two imaginal)! ra x~930B511 y=.00478157 y1=x~2x+1 One real rOO! (- .93,0) 1 22 N. Families of functions: Graphs of fu nct ion fami lies. Changes in values of the parent affect the appearance of the paren t g raph. A par ent g raph is the basic graph in a fam ily. II the other family m mbers move up, down, left. right, o r turn based on changes in values . I. Polynomial functions 1: a. f(x) = x2 (22) b. f(x) = 2x2 (23) c. f(x) = .5x2 (24) _ 2 d.f(x) - -x (25) e . f(x) = x2 + 2 (26) x2 f f(x) = 2 (27) g. r(x) = (x + 2)2 (28) h.r(x) = (x - 2)2 (29) 2. I>olynomial functions 2: a. f(x) = x3 (30) b. f(x) = _x3 (31) c. f{ x) = x3 + 2 (32) d.f(x) = x3 - 2 (33) e. f(x) = 2x3 (34) f. f( x) = .5x3 (35) g. f( x) = (x + 2)3 (36) h.f(x) = (x - 2)3 (37) 3. A bsolute value functions: a. f(x) = Ixl (38) b. f(x) = -Ixl (39) c. f{x) = 12xl (40) d.( f(x) = 1.5xl (41) e .f(x) = Ix + 21 (42) f. rex) = Ix - 21 (43) g . f(x) = Ixl + 2 (44) h. f(x) = Ixl- 2 (45) A. Rectangula r coordinates arc o f the form (x,y), and arc pl otted on the Cartes ian coord inate system. B. Poin ts are p lotted with two va lues, one the absci sa and the other th ordinate. C. The absc issa i the x-va lue, ca ll ed the domain. and the ord inate is the y-value, called the range. D. Many di ffe rent shape and func tion can be drawn on the Carte ian system. E. Here is a g iven ang le, orig inating fr III the -axi and rotating counter-clockwise. This angle is represented by a line segment ori ginati ng at t.he o rigin, and extend ing to a given point (P). (46) R Polar coordinates are of the fo rm P( r, 9), where r = the radiu , the di stance from the orig in (0,0) to I) (a g iven point), and El = the magnitude o f an angle. I. If r is pos itive, e is the meas ure o f any a ng le in sta ndard pos ition th at has segment 0 ,1' a its te rmina l s ide. 2. If r is negat ive, El is the measure of any angle that has th ray oppos ite segment O,P as its termina l side. (47&48) G. Graphing w ith polar coordinates : I. Example I: 1'(4, 120 d egrees) (49) 2. E xample 2: P ( 4. ~ ) (50) H. One angle graphed with polar coordinates can I' present severa l angle . I. If Pis a po int w ith polar coordinate (r, 9), then l' can Ef]S /P P(4.6) EB7, p I ( . P(H,O) EEJ P(-r,9) ffi P(4, 120) 2 also be g raphed by the po lar coordi nates (-r, e+ (2x + 1)1t) or (r, e+ 2x1t), where x i any in teger. 2. E xa mlJle: Show fo ur differ nt pa ir aofp la r coo rd i- rn. nate that can be re presented b the po int 1'(3, 60 I. degrees). 3. (-r, e+ (2x + 1)1 80 degrees) ~ (- (3), 60 + (1)180) (- (3), 60 - (1)1 80), = 1'(-3, 240) or 1'(-3,120) P(4'3) 4. (r, e+ 360x) ~ P(3, 60 + (1)360) or 1'(3, 60 + (2(360) = P(3, 780) hanging from rectangula r to pola r coordinates : The fo llowing fo rmulas are used to make this change: I. r = j( x 2 + y2) , e=A rctan f , x > O. 2. 9 =Arc tan f + 11:, X < 0, a nd fj = radians. 3. E xample I: Find the polar coordinates f, r 1'(-2,4). r = j _ 2)2 + (4 )2 = j20 = 4.47. e= Arctan _42 + 1t = 2.03, P(4.47, 2.03). ~_~ 4. Exam ple 2: Find the polar co rd inates for P(3 ,5). r = j()2 + 5 2) = 34 = 5.83, El = A rctan "35 = 1.03. P(5.83, 1.03). hanging from polar to rectangular coordinates: The formulas used to make this change are : I. x = r cos El 2. v = r sin e 3. ~~a~Ple 1: P ( 4. ~), x = 4 cos ( ~) = 2, and 4 s in (~) = 3.46 - P(2, 3.4(h. 4. Example 2: P(5, 60°), x = 5 cos (60) = -4.76. Y = 5 sin (60°) = -1.52 = P( -4. 76, -1.52). K. Grapbing imaginary numbers with po lar coord inate: The polar form of a complex number i x + yi = r(cos El + i s in e). Example: Graph the complex number -4, + 2i, and change to polar form. r = ;;r+yL = j( _ 4 2 + 2i 2) = /16 + 4 = ,fiO = 4.47, El = rctan ( _24 ) + IT = 2.68,1)0Ia r fo rm = 1'( -4, 2 i) = 4.47(cos 2.68 + i s in 2.68) A. Exponential properties: I. Multiplication: x· xh = x. + b Example: x2x4 = x6 2. Division : (;: ) = x·-b Example: (::..64)= x lO 3 . Distribution with multiplication : (xy)· = x·y· Example: (xy)s = xSy5 4. Distribu tion with d ivision: ( yr= x: Exam ple: ( y / = ( ;: ) y 5. Power of a power: (X")b = x· b Example: (x2)3 = x6 6. Inverse power: x-I = { Exa mple: x"" = ~ x 7. Root power: xI I. = .j; Example: XII2 = j; 8. Rational power: x· /b = bR Example: x312 = R B. Logarithmic Properties and Logarithmic Form: 11. Logarithmic Form: log.x = y, thi s is read a "the exponent of a to get the result x is y." EE Example: log, 100 = 10, the exponent of x to get the result .100 = 10 or xlO = 100. 2. Loga rithmic I)roperties : a. M ultiplication: log.xy = log.x + log.y b. Division: log. y= logax - log.y FE c. Power p roperty: log.xb = b * log.x d. rdentity property: If log.x = logaY' then x = y 3. Change of Base property: I Lx, y and z are + numbers. log ) z and x and }' are n t = I , then, log,z = -I -- . EBog)x C. Solving logarithmic equations: Example I: Write log 1000 = 3 in exponential form: 10" = 1000 Example 2: olve, log, Ii = i ~ xl/4 =Ii ~ EfJ (xI /4)4 = (1i)4 ~ x = 4. 5 Example 3: logi2x - 6) = log4(24 - 3x). 2x - 6 = t§24 - 3x. x = 6. Example 4: log (2x + 8) - log (x + 2) = I log 2 + 8) (2x + 8) (x +2 ) = I ~ = (x + 2) ~ 6101 IOx +20= 2x EEJ + 8 ~ 8x = -12 ~ x = - L5. x- 1/3 Exam ple 5: log, 5 = -* ~ = 5 ~ x = - 1~5. D. Graphing Exponent ial and Loga rithmic Equations: Exam ple I: y = 3 ', and (1/3)' on the same graph. (51) Example 2: y = 92+1 (52) Example 3: y = 22. - 1 - I (53) BtlExample 4: y = 22>-1 + I (54) Example 5: y = logz<x + 2) (55) Example 6 : y = log2(x - 2) (56) Example 7: y = log2(x - 2) + 2 (57) ttJ A. The notation P(n,n) = the number of permutations of n objects taken all at one time. B. The notat ion P(n,r) represents the number of perm utation of n obj cts I taken r at a time P(n,r) = !, P(n,r) = ( 11.) I'Il -r. C. The notation n! is read as n - factorial. Example I: How many ways can fi ve cartons of cereal be arranged? P(5,5) ~ 5! = 5432 I = 120 Example 2: If 18 people show up to serve on ajury, hO\ many 12 person 18!juries can be chosen? P(1 8, 12) ( 18 -12 ) ! 18·17·16·15·14·13·12·11·10·9·8·7·6·5·4 ·3·2·1 . h 6.5.4.3.2.1 , not!cetatyou can cancel 6!, leaving 18 ~ 7 = 8.89 X 10 12 choices. Example 3: A combination lock has four tumblers, and i num bered I 20 on the dial. How many combinations are possible . P(20,4) ~ ;gi _ 20·19·18·17·1 6 ·15·1 4 ·13·12·11·10· 9 · 8 · 7 · 6·5 · 4 ·3· 2 ·1 _ - 16·15· 14 · 13 ·12 ·11·1O·9· 8 ·7·6·5·4.J.2 ·1 116,280. Example 4: If26 people enter a 16-mile race and all of them finish, h w many possible orders of fin ishing are there? P(26,26) = 26! 26! = 4.032 x 1026 D. Permutations that contain repetitions or are placed in a Circular Pattern Repetitions: The number of n objects of which x & yare alike = ~. .y. C ircular Patterns = (n-I)! Example 1: How many word arrangements can be made from the word 5! radar? n = 5, x&y = a&r = 2. 2!2! = 30. Example 2: How many word pattern can be form ed from Mi issippi? ll! 2!2!2!4! = 207,900. Example 3: There are 24 ch ildren who are going to play dodge ball. 10 of them w ill start out in the circle. Ilow many ways cou ld the remai ning children fo rm ci rcular combinations? (n-I)! = 13! = 6,227,020,800. E. Combinations: Di ffer from permutations in that order i not a cons ider ation. The number of n objects taken r at a time is C(n,r) = ( II! ) . 11- r !r! Example 1: A book c lub ha selected e ight books to read, how many four group com binations are pos ible? ~ qn,r) = ( 8! ) = 708 - 4 !4! Example 2: How many five card hands an be dealt from a regu lar deck 52' of cards? qn,r) ~ = (52 _ 5) !5! = 2598960 A. Synthetic division is a method used to make long d ivision of p Iynomial les cumbersome. I . It is mainly used when you have a very long numeral r. 2. It can only be lIsed wi th a di i or in the form (x - n). 3. You can convert the form (3 x + n) to (x + 1/3n) and then use synthetic divis ion. B. Synthetic Division of the fo rm x2 - 3x - 54.;- x - 9. I. Example I: The standard way of d ividing polynomials x - 9 ) X 2 - 3x - 54 x + 6 x - 9 ) X 2 - 3x - 54 _(x2 - 9x) 6x - 54 -(6x - 54) o Answer = x + 6 r. 0 2. Using synthetic division, we use the econd part of the divi or, but change the sign (+9, trom the above example). We then Ii I the coefficients of the div idend. From the example above, th y \\ould be I , -3, -54. Then bring down the coefficients one at a time, mUltiply them b} the divisor (+9), and add them to the next coefficient. This gives the same result. From the example on pg. 3: 2..1 1 -3 -54 9 54 1 6 0 An wer = x + 6 r. 0 Note: The power of x a lways begins one lower in the answer. Exam ple 2: 3x3 + x2 + 5x - 2 -;.- x + 1 -? ::.113 1 5 -2 -3 2 -7 3 -2 7 -9 nswer = 3x2 - 2x + 7 r. -9 Example 3: In the following example, notice that there mu t be a place-ho lder fo r missing powers of the variable. Z4 + Oz3 + Oz2 + Oz + 16 -;.- z + 2 -21 0 0 0 16 -2 4 -8 16 I -2 4 -8 32 Answer = z3 _2z2 + 4z -8 r.32 C. S nthetic divi ion of the form 3x2 + lOx - 9 + 3x~2. In thi example, all number are first divided by 3, then at the end of the process a ll fractions are changed by mul tiplication. Exam pie 1: 3x - 2 ) ( 3x 2 + lOx - 9) become x - t ) ( X 2 + lj) x - t 10 - 9tl "3 3 2 8 3 3 1 4 - 3 Answer = x + 4 r. - t ' now mult iply a ll fract ions by 3. Answer = x + 4 r. -1. When th i same problem is performed with trad i tional divi sion, the an wer i the same. Exam ple 2: 2x - I )( 6x 4 - x3- Ilx 2+ 9x - 2), now div ide all parts by 2, and use s nthetic divis ion . 1 I I 9 t l 3 - 2 - 2 2 -I 3 I 5 2 2 - 2 3 -5 2 0 Answer = 3x3 + x2 -5x + 2 r. 0 Aga in, when standard long division is perform d, the same answer is atta ined . Note:I I' there w re any frac ti ons in a ny part of the an wer, they wou ld be removed by mul tip licat ion. MATRICES A. Matrix: rectangu lar array of elements in columns and rows. Rows are named before columns, therefore a 2x4matrix has two rows and four colwnn . B. Proper ties of Matrices: I. A matrix with on l one row is called a row matri x. 2. matri that ha onl. one olum ll i ca lled a colum n matrix . 3. Two matrices are equal if and only if they have the same dimensions and contai n the same identical e lements. 4. The sum or a 2x3 and a 2x3 matrix is a 2x3 matrix in which the e lements are added to the correspond ing e lements. 9 21 Exam ple: Find.1 + K ifJ = 1 2 4 -61 and K = f3 1-3 0 2 1 15 -3 -'i' .J +KJ5 13 - 4 1. 12 - 3 I I 5. The ditference of two matrices.J - K is equa l t adding J to the add itive 2 4 -61 1- -9 2 1 J inverse of K. .I = 1 and K = 1- 3 0 21 I 3 II J-K J -I -5 - 81 1-8 3 31 6. The product ofa scalar (x), (a va lue with magn it ude, but no direct ion), and a matrix (.I) is d, with each e lement f . .1 mu ltip lied time the S·· . I 12 24 - 36 1 I va ue x. IX tImes the matrIX .I = . 1-1 8 0 12 1 7. The product of 2 - two by t\\'o matrices i a two b two matrix. The procedure isa fo llow: .J = 12 41 ,1 6 9 1. 16 I I 13 21 JxK='2 ( 6 ) + 4( 3 ) 2 (9) + 4( 2 )IJ 24 26 1 [6 ( 6 ) + t( 3 ) 6 ( 9 ) + l( 2 ) 1 139 56 1 C. sing matnce to solve systems of eq uat ions: If you have thr e systems of eq uation you can use an augmented matrix to find the solu tion et of the va riable. You mu t fo llow the e guide li nes: I. Any two rows Illa be interc hanged. 2. ny row may be replaced by a non-zero multiple of that row. 3. Any row may be replaced by the um of that row and the multiple of another. The goa l is to achieve an augmented matrix of the form; 110 0 : x,1 10 I 0 : y I 100 I : z I, where x, y, z = the olution el. Example : Solve x - 2y + Z = 7 3x + Y - z = 2 2x + 3y + 2z = 7. u ing an augmented matrix. The augmented matri i I I -2 I: 7 I 13 I -I : 21 12 3 2: 71 Mult iply row I by -3 and add 10 rO\ 2 I I -2 I: 7 I 107-4:-19 1 12 3 2: 7 1 MUltiply row I by -2 and add to I' w 3 I I -2 I: 7 I 10 7 -4 :-19 1 10 7 0: -7 1 Mu ltiply row 2 by - I and add trow 3 II -2 I: 7 1 I 0 7 -4 : -1 9 I 100 4 : 12 1 Add row 3 to I' W 2 I 1 -2 I : 7 I 107 0 :-7 1 10 0 ~ : 12 1 Mu lt iply row 2 by 117 -2 1 I: 7 I 01 0: - I I 004 : 12 1 Multiply row .... by 1/4 I -2 I : 7 1 o I 0: -I I o 0 I: 3 1 Multiply row 2 by 2 and add to row I I 0 I : 5 I 010: -I i 00 1 : 3 1 Multiply row by -I and add to r w I 1 00 : 2 1 o I 0 : -I I 00 1 : 3 1 The solution set = 2, -I, 3. IS BN- 13 : 978 - 14 2320248- 6 IS BN- 10 : 142320 2 48 -1 U.S. 54.95 CAN. $7.50 Author: S. OrcuttJ~111111 IlI1lllllllil1llillllil "" rlpU, re)oo:n~J Nil ran Q(lh, pul.h,,;lil, .. I1'\1\ lit ICprod U' d ... IBII mil .. Ift.-\ r"nn vr b, an) mean~, 1:1«1100'''' Of rIW\n.n, •• Indu"h" pNII.,.;;"" rc..:.'I"d, .... "' .1\ ,"11,, 11\4111<.) 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