SOLUTION: An important trigonometric identity is cos(a + b) = cos a cos b − sin a sin b, which is called the cosine addition formula. Use this formula to show that cos2(a) = (1 + co

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Question 1082826: An important trigonometric identity is
cos(a + b) = cos a cos b − sin a sin b,
which is called the cosine addition formula.
Use this formula to show that cos2(a) = (1 + cos(2a))/2

Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
cos2(a)
-----------
Is that
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Use ^ (Shift 6) for exponents.

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