若sin(30-x)=1/3,则cos(120+2x)等于?如题,请说明过程,

若cos x-sin x = 0.5,则cos^3 x-sin^3 x = 若sin x/2 - cos x/2 = 1/3,则sin x=? 若sin x/2-cos x/2=1/3,则sin x= 若cos(x+y)cos(x-y)=1/3,则cos^x-sin^y=?^为平方 若SIN X*COS X =1/3,已知0 若F(sin x)=3-cos 2x 则F（cos x）=? 若sinx+sin^2x=1,则cos^2x+cos^4x=? 证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4 已知(1+sin x)/cos x=-1/2,则cos/(sin x-1)=? 若f（sin x+cos x）=sin x·cos x,则f（cos 派/6）=? 若方程12x²+πx-12x=0的两的根分别是α,β,则cosαcosβ-√3sinαcosβ-√cosαsinβ-sinαsinβ= 若sin(pai/6-x)=1/3,则cos(2pai/3+2x)=? 若sin(兀/3-x)=1/4,则cos(兀/3+2x)等于多少 若cos²x+sin2x-3sin²x=1则tanx= 若1+cosα/sinα=2 则cosα-3sinαRT... 若sin(30-x)=1/3,则cos(120+2x)等于?如题,请说明过程, Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) 若cos(α-β)=1/3,则(sinα+sinβ)^2+(cosα+cosβ)^2=?