Calcule as seguintes expressões trigonométricas: (a) cos 105o; (b) tan 15o; (c) sen 13π/12; (d) sen 22o30′; (e) tan 22o30′.

(a) cos 105° = -cos(180°-105°) = -cos75° = -√6 + √2/4 (b) tan 15° = tan(45°-30°) = (1-tan30°)/ (1+tan30°) = 2-√3 (c) sen 13π/12 = sen(π-13π/12) = -sen(π/12) = -√(2-√3)/2 (d) sen 22°30' = sen22°cos30' + cos22°sen30' = (1/2)sen22° + (√3/2)cos22° (e) tan 22°30' = sen22°30'/cos22°30' = (2-√3)/(√3-1) = 2+√3