Question

verify the identy
cos4u=cos^2(2u)-sin^2(2u)

Answer 1

4u = 2(2u)

Also, cos(a + b) = cos a cos b - sin a sin b so cos 2c = cos² c - sin² c

Answer 2

this is one of the trig identities:
cos^2x-sin^2x=cos2x
can u solve it from dere?

Answer 3

Can you do it from here? @Twalt13