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Homework Help: Trig Identity proof

  1. Apr 6, 2013 #1


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    1. The problem statement, all variables and given/known data

    Prove the identity:


    2. Relevant equations

    3. The attempt at a solution

    Starting with the LHS:


    And thats as far as I can see to rearrange it.
  2. jcsd
  3. Apr 6, 2013 #2


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    Now just substitute your identities for cos2θ and sin2θ and it should work out easily.
  4. Apr 6, 2013 #3


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    Woops I forgot about the double angle formulae

    so the rest of it is:

    ∴ LHS = RHS
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