Question

cos 4x + cos 2x = 2 - 2 sin^2 2x - 2 sin^2 x
verify the identity.
I really dont understand this so if you can show steps to it too thatd be great:)

Answer 1

Take the identities on the left side.
cos2x=1-2sin^2x
cos4x=cos2(2x)=1-2sin^2(2x)

Answer 2

Getting it @beachgirl129?

Answer 3

um I think like i see how you did those steps but once I get 1-2sin^2(2x) how will i get it to equal the right

Answer 4

cos4x+cos2x=1-2sin^2(2x)+1-2sin^2x

Answer 5

ohhhkay thanks:)

Answer 6

welcome:)