Tolong kerjakan no 5, terima kasih

cos 2x-sinx = 0
1-2sin^2x - sinx= 0
2 sin^2x+ sinx -1 = 0
2a^2+a-1 = 0
(a+1)(2a-1)=0

a=-1
sinx = -1
maka x = (270)

sinx = 1/2
x = (30,150)

Hp (30,150,270)