SOLUTION: Verify the identity. Be sure to show each step. cos(x + y) + cos(x

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Question 942867: Verify the identity. Be sure to show each step.
cos(x + y) + cos(x - y) = 2 cos x cos y
Answer by TimothyLamb(4379) (Show Source):
You can put this solution on YOUR website!
trigonometric identities:
cosine of sum, cosine of difference:
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cos(x + y) = cosx cosy - sinx siny
cos(x - y) = cosx cosy + sinx siny
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cos(x + y) + cos(x - y) = cosx cosy - sinx siny + cosx cosy + sinx siny
cos(x + y) + cos(x - y) = cosx cosy + cosx cosy - sinx siny + sinx siny
cos(x + y) + cos(x - y) = cosx cosy + cosx cosy + 0
cos(x + y) + cos(x - y) = 2 cosx cosy
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SOLUTION: Verify the identity. Be sure to show each step. cos(x + y) + cos(x - y) = 2 cos x cos y