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Help with hard intergration

  1. Oct 6, 2008 #1
    I am stuck on an intergration and can't get a simple answer which i should get

    p = (2*m*l^2)^(1/2)*(E+m*g*l*cos theta)^(1/2)

    using small angle (need for question) cos theta = 1 - (theta^2 )/2

    Then I intergrate from 0 to 2*Pi and get some very large eqn using a maths program, I can't think how I would do it by hand?

    Can anyone help with the problem
  2. jcsd
  3. Oct 6, 2008 #2


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    Science Advisor

    So basically, the problem is to find the integral (a+ bcos(theta))1/2? That looks like an "elliptic integral" to me- there is no way to do it in terms of elementary functions.

    You mention the "small angle" approximation but, of course, 2pi is NOT a "small angle".
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