Answer:
Step-by-step explanation:
3 sinθ=3 cos 2θ
sin θ=cos 2θ
sinθ=1-2sin² θ
2sin²θ+sin θ-1=0
2sin²θ+2sinθ-sinθ-1=0
2sin θ(sin θ+1)-1(sin θ+1)=0
(sin θ+1)(2 sin θ-1)=0
sin θ=-1=-sin 90=sin (180+90)
θ=270
or sin θ=1/2=sin 30,sin (180-30)
θ=30,150
solution set is {30,150,270}
