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Extremely hard integral - pls help

  1. Oct 28, 2012 #1
    1. The problem statement, all variables and given/known data
    integrate the following function: x*√(2x-x2)

    2. Relevant equations

    3. The attempt at a solution
    I substituted x with x=2sin2u. From that I ended up with ∫x*√(2x-x2)= 16∫sin4u*cos2u

    Now I'm supposed to use a formula from an integrals table.. but which?
  2. jcsd
  3. Oct 28, 2012 #2


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    You should complete the square under the sqrt. [itex] \displaystyle{\sqrt{1-(1-x)^2}}[/itex] and then make the natural substitution.
  4. Oct 28, 2012 #3
    edit: nvm
    Last edited: Oct 28, 2012
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