Verify the identity Cos^2x-Sin^2x=1-2sin^2x
\(cos^2x-sin^2x=1-2sin^2x\\\\\\R=1-2sin^2x=cos^2x+sin^2x-2sin^2x=cos^2x-sin^2x=L\\\\\\\\\\sin^2x+cos^2x=1\)
