MHB Integral from negative infinity to infinity

[juantheron]

$\displaystyle (1)\;\; \int_{-\infty}^{\infty}\frac{x^2}{1+4x+3x^2-4x^3-2x^4+2x^5+x^6}dx$

 

[CaptainBlack]

\[\int_{-\infty}^{\infty}\frac{x^2}{1+4x+3x^2-4x^3-2x^4+2x^5+x^6}dx=\pi\]

Now can you tell us in what context this arises.

CB