(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

prove that cos^4(x)= 3/8 +1/2(cos2x)+1/8(cos4x)

2. Relevant equations

3. The attempt at a solution

i attempted to change the cos2x to 2cos^2(x)-1.....then made all them over 8....and now im stuck......another question....if i multiply 2cos(4x) by 2, do i multiply the 2 and the 4x? or just he 4x?

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# Homework Help: Trig identity

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