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Homework Help: Trig and double angle integration

  1. Feb 4, 2013 #1
    1. The problem statement, all variables and given/known data
    ∫sin(t)cos(2t)dt


    2. Relevant equations
    cos(2t)=1-2sin^2(t)


    3. The attempt at a solution
    ∫sint(t)(1-2sin^2(t))dt
    but where do i go from here? i cant use substitution. or parts?
     
  2. jcsd
  3. Feb 4, 2013 #2
    cos2x can also = 2cos2x-1, if you make it that, then this is a simple u-substitution..
    u=cosx
     
  4. Feb 4, 2013 #3
    thankyou very much! i just didnt exhaust my formulas..
     
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