Question

Nilai x di antara 0 dan 2phi yang memenuhi persamaan: cos^2x + cosx-2=0 adalah....

Answer 1

Cos² x + cos x - 2 = 0
(cos x -1)(cos x + 2) = 0
cos x - 1 = 0 atau cos x + 2 = 0

cos x - 1 = 0
cos x = 1
cos x = cos 0
x = 0 + k.360
k = 0, x = 0
k = 1, x = 360

HP = {0, 360}