Cos (4x+ 1/3 π ) = cos 5/6π unruk 0 kurang dari sama dengan x krangdari sama dengan 360

TriGonoMetRi

Interval : 0° ≤ x ≤ 360°
π = 180°

cos (4x + 1/3 π) = cos 5/6 π
cos (4x + 60°) = cos 150°
•
4x + 60° = 360° - 150°
4x = 210° - 60°
x = 150°/4
x = 37,5°

••
4x + 60° = -150°
4x = -150° - 60°
x = -210°/4
x = -52,5°
x = 360° - 52,5°
x = 307,5°


Nilai x yg memenuhi :
x = 37,5°
x = 307,5°