Cos^2 x+3sin x-3=0
cos^2x+3sinx-3=0
1-sin^2x+3sinx-3=0
-sin^2x+3sinx-2=0
sinx=y
-y^2+3y-2=0
y^2-3y+2=0
D=1
y1=2
y2=1
sinx=1
x=П/2+2Пn