SOLUTION: Prove the following identities (i) cos2A + cos4A + cos6A + cos12A = 4cos3Acos4Acos5A (ii) cos3Acos8A + sin4Asin7A = cosAcos4A

Algebra ->  Test -> SOLUTION: Prove the following identities (i) cos2A + cos4A + cos6A + cos12A = 4cos3Acos4Acos5A (ii) cos3Acos8A + sin4Asin7A = cosAcos4A      Log On


   

Question 1135197: Prove the following identities
(i) cos2A + cos4A + cos6A + cos12A = 4cos3Acos4Acos5A
(ii) cos3Acos8A + sin4Asin7A = cosAcos4A
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
cos2A
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Is that cos%5E2%28A%29 ?
Or cos(2A) ?
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If you don't have time to make it clear, I don't have time to work it.