teman2 tolong kah dijawab bsok mau dikumpulkan pakai cara yah no 11

cos 2x - sin x = 0
1- 2 sin^2 x - sin x = 0
2 sin ^2 x + sin x - 1 = 0
(2 sin x - 1) (sin x + 1)
2 sin x = 1 sin x = -1
sin x = 1/2 x = 270°
x = 30° & 150°

maka HP = {30° ,150° , 270°}
= {30Π/180° , 150°Π/180°,270Π/180°}
= {Π/6 , 5Π/6, 3Π/2}

jawabannya yg B