Question

Nilai x yang memenuhi persamaan 2 cos (2x-60°) = -√3 untuk 0° ≤ x ≤ 360° adalah ....

Answer 1

Verified answer

Bab Trigonometri
Matematika SMA Kelas X

2 cos (2x - 60°) = -√3
cos (2x - 60°) = - (1/2) . (√3)

2x - 60° = 150° 
2x = 150° + 60°
x = 210°/2
x = 105°

2x - 60° = 210°
2x = 210° + 60°
2x = 270°
x = 135°

2x - 60° = 150° + 1 x 360°
2x - 60° = 510°
2x = 510° + 60°
x = 570°/2
x = 285°

2x - 60° = 210° + 1 x 360°
2x = 570° + 60°
x = 630°/2
x = 315°

HP = { 105°, 135°, 285°, 315° }