Question

se cos= -12/13, pi < x < 3pi/2, calcule o valor de tgx

Answer 1

cos x = -12/13
sen²x + cos²x = 1
sen²x + (-12/13)² = 1
sen²x + 144/169 = 1
sen²x = 1 - 144/169
sen²x = 169/169 - 144/169
sen²x = (169-144)/169
sen²x = 25/169
senx = \/(25/169)
senx = 5/13

tg x = sen x / cos x
tg x = 5/13 / -12/13
tg x = 5/13 . -13/12
tg x = -5/12

Answer 2

Ola Anajulia

cos²(x) + sen²(x) = 1

144/169 + sen²(x) = 169/169

sen²(x) = 25/169

sen(x) = -5/13  (negativo no terceiro quadrante)

tg(x) = sen(x)/cos(x) = (-5/13)/(-12/13) = 5/12