Cos(x+y)=cosxcosy-sinxsiny show sin2x cos2x

1.	Cos(x+y)=cosxcosy-sinxsiny show sin2x cos2x
Answer» Cos(x+x) = cosxcosx-sinxsinxCos2x = cos^2 x - sin^2 x = 2cos^2 x - 1 =1 - 2sin^2 xWe know that sin(x+y) = sinxcosy+cosxsiny => sin(x+x) = sinxcosx+cosxsinx => sin2x = 2sinxcosx

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