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Homework Help: Trigonometric identity

  1. May 6, 2015 #1
    IMG_20150506_165135408.jpg I am doig trigonometric identities and i got this one, (all will be in the picture the solution and my work) i used the double angle for this but i am afraid i didn't get the exact idea, just guessing, good guessing, so i want to know how is the proper way to reach the solution
  2. jcsd
  3. May 6, 2015 #2


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    Here is a little bigger view for folks.


    So, I take it that you want to simplify ##\ \sqrt{1+\cos(6\theta)\,}\ ## using the double angle identity for cosine.

    Write 6θ as 2(3θ) .
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