化简sin(-2x)

化简 cos^2(x)*sin^2(x)-sin^2(x) 化简 cos^(2)(x)*sin^(2)(x)-sin^(2)(x) 化简(sin^2 x/sin x-cosx)-(sin x+cosx/tan^2 x-1) 化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x 化简sin(2x-y)*sin y+cos(2x-y)*sin y 化简!f(x)=sin(pai-x)cos(3/2pai+x)+sin(pai+x)sin(3/2pai-x) 化简sin（2π+x）cos（π-x）sin（π-x）/cos（x-π）sin（-π-x）sin（π+x） 化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x) 化简 1/2cos x-根号3/2sin x 根3sin x+cos x 2cos2x+sin^2x 化简 sin(3π/2-x)化简 化简cos^4x+sin^2xcos^2x+sin^2x