How can you prove:(adsbygoogle = window.adsbygoogle || []).push({});

[tex]cos(A+B)=cosAcosB-sinAsinB[/tex]

and similarly

[tex]sin(A+B)=sinAcosB+cosAsinB[/tex]

If the proofs arent very complicated, I would appreciate you giving me hints first so maybe i can work them out on my own.

Btw i am looking for an algebraic proof, not one with graphs & triangles.

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# 2 Proofs

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