当cos^2x-cos^2y=√3/2时,求sin(x+y)×sin(x-y)

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当cos^2x-cos^2y=√3/2时,求sin(x+y)×sin(x-y)当cos^2x-cos^2y=√3/2时,求sin(x+y)×sin(x-y)当cos^2x-cos^2y=√3/2时,求

当cos^2x-cos^2y=√3/2时,求sin(x+y)×sin(x-y)
当cos^2x-cos^2y=√3/2时,求sin(x+y)×sin(x-y)

当cos^2x-cos^2y=√3/2时,求sin(x+y)×sin(x-y)
∵ cos^2x-cos^2y=(cosx-cosy)(cosx+cosy=)= -2(sin(x/2-y/2))(sin(x/2+y/2))(cos(x/2-y/2))(cos(x/2+y/2))= -sin
(x-y)sin(x+y)=√3/2∴sin(x-y)sin(x+y) = -√3/2