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Math Help - Definite integral using contour integration.

  1. #1
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    Definite integral using contour integration.

    Hi

    i need help in solving this integral for this specific integration limit:

    int (0) to (pi/2) {cos (2 theta)/(cos(theta)-x)}dtheta abs (x)<1

    Appreciate your help

    mopen
    Last edited by mr fantastic; October 19th 2011 at 04:35 AM. Reason: Re-titled.
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  2. #2
    MHF Contributor FernandoRevilla's Avatar
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    Re: i need help solving this integral.

    If the problem has been proposed in the context of complex variable, use the substitution z=e^{i\theta} .
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  3. #3
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    Re: i need help solving this integral.

    yes, i did that but the problem is that i got imaginary part of the solution, but i think the integral should be real.
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  4. #4
    MHF Contributor FernandoRevilla's Avatar
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    Re: i need help solving this integral.

    Quote Originally Posted by mopen View Post
    yes, i did that but the problem is that i got imaginary part of the solution, but i think the integral should be real.
    Indeed, the solution must be real. Please, show your work an we can check it.
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  5. #5
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    Re: Definite integral using contour integration.

    Hi
    i have attached two different solution for the problem. from the first one i got unexpected results at low x and at the second one i got imaginary part of the solution.

    So any help with the problem!

    thanks

    mopen
    Attached Files Attached Files
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