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Homework Help: I forgot how to do this integration Help

  1. Jul 5, 2011 #1
    1. The problem statement, all variables and given/known data

    Do the integration

    2. Relevant equations


    3. The attempt at a solution

    I forgot how to do this integration with another method. I think I can do it through Trigonometric Method. But I remember that there is still another way to do it without using Trigonometric Method. Anyone can show me steps to do it? Thanks.
  2. jcsd
  3. Jul 5, 2011 #2
    Well, for the trig method you would use the substitution let x = ytan(u)
    If that gets you the right answer then why bother with another method. I can't think of a different method right now that would work.
  4. Jul 5, 2011 #3


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    Take the derivative of [itex]\displaystyle \frac{x}{y^2\sqrt{x^2+y^2}}\,,[/itex] treating y as a constant, of course. Then see if you can reverse the process.
  5. Jul 5, 2011 #4


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    Try a substitution [itex] x=y \sinh t [/itex]. The resulting integration will be trivial.
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