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Simple Calculus (indefinite integral)

  1. Nov 19, 2012 #1
    1. The problem statement, all variables and given/known data

    Find the indefinite integral:
    ∫ Cos32x Sin22x dx

    2. Relevant equations

    None required

    3. The attempt at a solution

    Lost on where to start. If someone could just start me off.
     
  2. jcsd
  3. Nov 19, 2012 #2

    lurflurf

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    either use the identity
    cos3(2x)sin2(2x)=(1/16) (2 cos(2 x)-cos(6 x)-cos(10 x))
    or
    cos3(2x)sin2(2x)=(1/2)(sin2(2 x)-sin4(2 x))(sin(2x))'
    and the substitution u=sin(2x)
     
  4. Nov 20, 2012 #3

    SammyS

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    Write cos3(2x) as cos(2x) cos2(2x)

    Then use the identity,
    cos2(2x)=1-sin2(2x)​
    After that, a simple substitution should work fine.
     
  5. Nov 20, 2012 #4
    Knocked it out, thanks guys.
     
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