kak tolong bantuanya ya

cos 2x - sin x - 1 = 0
(1 - 2 sin² x) - sin x - 1 = 0
2 sin² x + sin x = 0
sin x (2 sin x + 1) = 0
sin x = 0 ---> x = 0° , 180°
sin x = -1/2 ---> x = 210° , 330°

Interval : 0 < x < 360

HP = {180° , 210° , 330°}