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

cos(a+b)

2. Relevant equations

find formulas for above

3. The attempt at a solution

cos (a+b)

= cos (a-(b))

=cos(a)cos(-b) + sin(a)sin(-b)

=cos(a)cos(b) - sin(a)sin(b)

I been scratching my head at this for hours now, and I still can't figure out how this works.

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# Homework Help: Solve Cos(a+b)

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