Question

Verify the identity.

cos 4x + cos 2x = 2 - 2 sin2 2x - 2 sin2 x

Answer 1

looks like this
\[\cos4x+\cos2x=2-2\sin^22x-2\sin^2x\]

Answer 2

using the double angle identity for cos
cos2x=-2sin^2(x)+1
and
cos4x= -2sin^2(2x)+1
so cos4x+cos2x
\[(-2\sin ^{2}2x+1)+(-2\sin ^{2}x+1)\]

Answer 3

remove the brackets and u will get the right hand side...

Answer 4

@LynFran sup

Answer 5

alright, Thank you!

Answer 6

@LynFran sup its me Peachesjpg I changed my name y u blocked me