Hello everyone, I have the this inquiry: if I compute de following integral: http://micurso.orgfree.com/Picture1.jpg by numerical methods I get cero as a result. I used Maxima and Mathematica and their functions for numerical integration give me an answer equal to cero. But, if I apply transformation with spherical coordinates the result turns out to be equal to pi^2 / 40. I can't seem to find an explanation for this. Could any of you guys give me a hand with this? Thank you in advance.