(1)y=2sin^2 x-cos x-1 最小值 (2)y=sinxcos(x-π/3)+sinxcosx最值 (3)y=sinxsin(π/2+x)+2sin^2x-1最值求答案阿!要具体步骤阿

(1)y=2sin^2 x-cos x-1 最小值 (2)y=sinxcos(x-π/3)+sinxcosx最值 (3)y=sinxsin(π/2+x)+2sin^2x-1最值
求答案阿!
要具体步骤阿

1)3/2
2)(根号3)/4
－(3根号3)/4
3)(根号5)/2
-(根号5)/2