Question

X dari 4 cos^3 x - 4 cos^2 x - cos x + 1 =0

Answer 1

4 cos^3 x - 4 cos^2 x - cos x + 1= 0
(cos x -1)(2 cos x -1)(2cos x +1) = 0
cos  x= 1 atau cos x = 1/2  atau cos x = - 1/2
jika 0 ≤ x ≤ 360
cos x = 1 --> x = 0 dan 360
cos x = 1/2 --> x = 60 dan 300
cos x  = -1/2 --> x = 120 dan 240
x  = 0, 60, 120 , 240, 300, 360