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Homework Help: Challenging triple integral

  1. Jun 9, 2008 #1
    1. The problem statement, all variables and given/known data

    Find [tex]\int\int\int\sqrt{x^2+y^2+z^2}e^{-x^2-y^2-z^2}dxdydz[/tex]
    The limits of integration for all 3 variables are from -infinity to infinity.

    2. Relevant equations
    This one has me completely stumped, so I'm just wondering if someone could push me in the right direction in how to solve this one. I thought about maybe finding a suitable substitution for the region of integration but I'm not sure at how that might work.
  2. jcsd
  3. Jun 9, 2008 #2


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    Hi HclGuy! :smile:

    Hint: change the variables of integration from x y and z to … ? :smile:
  4. Jun 9, 2008 #3
    Are you hinting towards spherical coordinates...?
    I'm gonna try that out.. Thanks
  5. Jun 9, 2008 #4
    becomes trivial once you change variables
  6. Jun 9, 2008 #5
    Thanks guys, got it now.
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