Tentukan semua solusi dari persamaan-persamaan trigonometri 2 sin^2 x + 3 cos x - 3 = 0 dengan x =[0,360]

2 sin² x + 3 cos x - 3 = 0
2 (1 - cos² x) + 3 cos x - 3 = 0
2 - 2 cos² x + 3 cos x - 3 = 0
2 cos² x - 3 cos x + 1 = 0
2 cos² x - 2 cos x - cos x + 1 = 0
2 cos x (cos x - 1) - 1 (cos x +1) = 0
(2 cos x - 1) (cos x -1) = 0

2 cos x - 1 = 0
cos x = 1/2
cos x = cos 60°

x = 60° + k. 360°
k = 0    x = 60°

x = -60° + k. 360°
k = 1    x = 300°

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°, 60°, 300°, 360°}