Hi,

I dont understand the cauchy theorem.

I have this problem and I would like to have some help for it.

The question is:

Use the Cauchy Integral Theorem to prove that:

$\displaystyle \int_{-\infty}^{+\infty}\frac{1}{x^2-2x+5}dx=\frac{\pi}{2}$

When I read the documentation on it , it is told to have a close surface . but here it is not specify...Or I just don't get it.

Thank you for your help.

B