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shannieboo4
Jan 31, 2012, 06:52 PM
Verify cos^2(x)-sin^2(x)=1-2sin^2(x)

Aurora2000
Feb 1, 2012, 02:00 AM
Start from identity
\cos^2x+\sin^2x=1
subtract 2\sin^2x both sides and you get
\cos^2x-\sin^2x=1-2\sin^2x