Tentukan himpunan penyelesaian persamaan dari soal berikut.

1.
sin (π/2 - 2x) = 1/2
sin (90° - 2x) = sin 30°
90° - 2x = 30°
2x = 90° - 60°
x = 30°/2
x = 15°

sin (90° - 2x) = sin 150°
2x = 90° - 150°
x = -60°/2
x = -30°
x = 360° - 30°
x = 330°

HP = {15° , 330°}

2.
cos² x + 3 sin x + 3 = 0
(1 - sin² x) + 3sin x + 3 = 0
-sin² x + 3sin x + 4 = 0
(-sin x + 4)(sin x + 1) = 0
sin x = -4 (tdk memenuhi)
sin x = -1 ---> x = 270°

HP = {270°}