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Homework Help: Integrating x * (cos x)^ n between pi/2 and 0

  1. Aug 5, 2011 #1
    Would anyone be able to help me do this? I have tried by parts, but did not make progress. As n gets large, the area gets smaller.

    Your help is appreciated.

  2. jcsd
  3. Aug 5, 2011 #2


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    Homework Helper

    You might apply that cos(x)=(eix+e-ix)/2

  4. Aug 6, 2011 #3
    Try integration by parts just once and use the formula for ∫cosnx dx twice.
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