(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=

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(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=(COSx)^2

(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=
(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=

(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=
由条件,有(1 cos2x)/2-(1 cos2y)=a 即cos2x-cos2y=2a sin(x y)*sin(x-y) =(sinx)^2*(cosy)^2-(siny)^2*(cosx)^2 对这个式子中各项降幂,可得 原式=(cos2y-cos2x)/2 =-a