Question #a0abc

1 Answer
Apr 22, 2016

Proof below

Explanation:

To me this looks more like a proving question than a solving question (because as you'll see if you graph it, it's always equal)

The proof:
1-2cos^2x+2cos^4x=1-2cos^2x+cos^4x+cos^4x12cos2x+2cos4x=12cos2x+cos4x+cos4x
=1-2cos^2x+(cos^2x)^2+cos^4x=12cos2x+(cos2x)2+cos4x
=(1-cos^2x)^2+cos^4x=(1cos2x)2+cos4x
=(sin^2x)^2+cos^4x=(sin2x)2+cos4x
=sin^4x+cos^4x=sin4x+cos4x