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Help with integral

  1. Nov 29, 2007 #1
    I accept any suggestion in how to work out the integral below. It is a simplification of an integral over all k space. It had 16 terms and I am down to this 4. The idea is to integrate it from 0 to pi in respect of x, and y.

    int{int{(-1-4 cos(x)^2*cos(y)^2+4cos(y)^2+cos(x)^2) / (1+4cos(y)^2+4cos(y)cos(x)dx}dy}

    both with limits from 0 to pi.

    Examples are:

    int{int{sin(x)^2*cos(y)^2 dx}dy} = 1/4 pi.

    I tried maple and matematica but didn't work. I strongly believe it is suppose to come out as a nice round integer number.

  2. jcsd
  3. Nov 30, 2007 #2
    \int{\int{/frac{(-1-4 cos(x)^2*cos(y)^2+4cos(y)^2+cos(x)^2)}{(1+4cos(y)^2+4cos(y)cos(x)}dxdy[/tex]?
    Last edited: Nov 30, 2007
  4. Nov 30, 2007 #3
    Same integral (latex version)

    Yeah, it looks llike:

    [tex] \int_{0}^{\pi} \int_{0}^{\pi} \frac{-1-4 cos(x)^2 cos(y)^2+4cos(y)^2+cos(x)^2}{1+4cos(y)^2+4cos(y)cos(x)}dx dy[/tex]

    As explained before, this are the last terms of a 16 terms integral, all the other came to be integers.
    Last edited: Dec 1, 2007
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