I have a few questions that I need help with for my precal class in college. The following have to prove the trigonometric identities:

cos4x + 2cos2x sin2x + sin4x = 1

sin4x - cos4x = 1 - 2cos2x

thanks you,


Hi Mandy.

Here's a hint that's good for both of those questions:

Try factoring them and then using the identity cos2x + sin2x = 1.

Hope this helps!
Stephen La Rocque>