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

Derive from Demoivre's theorem that

cos2theta=(costheta)^2-(sintheta)^2

sin2theta=2sin theta costheta

2. Relevant equations

3. The attempt at a solution

I really am clueless on this.

I considered using (costheta +isintheta)^n, but don't know where to go with this idea.

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# Homework Help: Deriving DeMoivre's Formula?

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