I'm having trouble with these two proofs.(adsbygoogle = window.adsbygoogle || []).push({});

cos(n∏+θ)=(-1)^n cos θ

ln|sec x|= -ln|cos x|

I know for the first one that I have to incorporate log somehow but that's about all I got from it.

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# Homework Help: Help w/ these proofs!

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