Question

3sin^2(x-3pi/2) - cos(x+4pi) =0

Answer 1

3sin²(x-3pi/2)=3cos²x      Cos(x+4pi)=cosx

3cos²x-cosx=0

cosx(3cosx-1)=0

cosx=0    3cosx-1=0

x=pi/2+Пk      cosx=1/3   x=arccos1/3+2Пn