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Homework Help: Integral calculation

  1. Dec 23, 2008 #1
    1. The problem statement, all variables and given/known data
    Calculate the integral:

    [tex]\int x \frac{dx}{\sqrt{(a^2+x^2)^3}}[/tex]

    where [tex]a\in R[/tex]

    2. Relevant equations

    3. The attempt at a solution
    I solved "similar" integrals like [tex]\int \frac{dx}{\sqrt{a^2+x^2}}[/tex]

    and [tex]\int \frac{dx}{x(x^2+1)}[/tex]

    but none of the approaches I know (and used for the above) seem to work. Not sure how to start here. Any ideas?
  2. jcsd
  3. Dec 23, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Just try substituting u=x^2+a^2. Your integral is even easier than the other two.
  4. Dec 24, 2008 #3
    Yes, it was. I was making a silly mistake.

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