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Homework Help: Double integral tough

  1. Jun 5, 2010 #1
    1. The problem statement, all variables and given/known data

    [itex] \int_{0}^{1} \int_{0}^{1} \sqrt{4x^2 + 4y^2 + 1} dx\,dy [/itex]

    3. The attempt at a solution

    This integral is tough for me, I couldn't think of a way to evaluate it. Can you suggest me the first step to do this problem?

  2. jcsd
  3. Jun 5, 2010 #2


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    Homework Helper

    The sum of squares strongly suggests a change to spherical coordinates (in 2D, that would be polar coordinates).

    An integral like
    [tex] \int r \sqrt{1 + r^2} \, dr [/tex]
    is easier, because r is the derivative of 1 + r2.
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