I recently read an article in a math magazine where some guy found anlges (A and B) when sin(A+B)=sinA + sinB. I have been trying to work with cos(A+B) and see if there are instances when cos(A+B) would equal cosA+cosB. Any ideas?(adsbygoogle = window.adsbygoogle || []).push({});

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# When does cos(A+B)=cosA +cosB

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