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Divergent Integral and Mathematica

  1. Jul 3, 2008 #1
    Hi,

    I am trying to calculate a double integral, in Mathematica it could be denoted

    Integrate[(x*y)/(x*y-m2/s2),{x,0,1},{y,0,1-x}]

    That is,

    [tex]\int[/tex][tex]\int[/tex][tex]\frac{xy}{(xy-m^{2}/s^{2})}[/tex]dydx with boundaries y=0,y=1-x and x=0,x=1. m and s are constants, of course.

    Now, I get some fairly crazy-looking and unhelpful results for the y-integral from Mathematica but I simply used a table of integrals and plugging in obtained

    1-x+[tex]\frac{1}{x}[/tex]*[tex]\frac{m^{2}}{s^{2}}[/tex]*Ln|x-x^{2}-[tex]\frac{m^{2}}{s^{2}}[/tex]|

    Now of course when I integrate this from x=0 to x=1 then I have a problem as x goes to 0. Someone suggested using interpolation somehow but I know very little about that and don't see if this is where to apply it. I don't think the integral should be infinite - perhaps the y-integral was wrong?

    Any help would be much appreciated!
     
  2. jcsd
  3. Jul 3, 2008 #2
    I should have had a denominator of m^2/s^2 in the log there, or subtracted a log|^2/s^2|.

    Anyway, that is not the problem...
     
    Last edited: Jul 3, 2008
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