Prove that Cos4x= 1- 8sin^2xcos^x

1.	Prove that Cos4x= 1- 8sin^2xcos^x
Answer» Taking LHS cos4x= cos2 (2x) = 1- 2sin^2x = 1- 2 ( 2sinxcosx)^2 = 1-2 (4sin^2xcos^2x) = 1-8sin&2xcos^2x

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