SOLUTION: Rewrite the product as a sum involving sine and/or cosine cos(-4a)cos(-7a)

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Question 959051: Rewrite the product as a sum involving sine and/or cosine cos(-4a)cos(-7a)
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Rewrite the product as a sum involving sine and/or cosine cos(-4a)cos(-7a)
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= (1/2)[cos[-4a-7a]+cos(-4a+7a)]
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= (1/2)[cos[-11a)+cos[3a]]
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Cheers,
Stan H.
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