Answer:
Step-by-step explanation:
3 sin²x-2cos x-3=0
3(1-cos² x)-2 cos x-3=0
3-3 cos²x-2 cos x-3=0
-3 cos ²x-2 cos x=0
cos x( -3cos x-2)=0
cos x=0
x=(2n+1)π/2,where n is an integer.
or -3 cos x-2=0
3 cos x=-2
cos x=-2/3
x=cos ^{-1}(-2/3)≈131.81°
