# Inconsistence in integral

1. Feb 9, 2005

### secret2

I am trying to do the integration

$$\int_{0}^\infty \frac{x}{(x^2+c^2)^3} dx$$

At first I tried doing it with contour integration, but yielded zero. Later I figured out that it can actually be done simply by making a change in variable (squeezing the x in the numerator into the dx). Is it possible to do it with contour integration (though not necessary)?

Last edited: Feb 9, 2005
2. Feb 9, 2005

### dextercioby

Since it doesn't have real poles (thre denominator does not cancel in R),why didn't u try to do it only by the obvious substitution.I'm sure the result will not be awkward.

Daniel.