# Integration!!!

• Nov 9th 2007, 09:07 PM
clipperdude21
Integration!!!
I havnt done calculus in a while and need help doing this integral... Im pretty sure it has to do with integation by parts but am not sure. <br><br>Integral of&nbsp; x^2e^(-kx)&nbsp; with limits 0 to positive infinity. Thanks!!! <br>
• Nov 9th 2007, 10:09 PM
kalagota
Quote:

Originally Posted by clipperdude21
I havnt done calculus in a while and need help doing this integral... Im pretty sure it has to do with integation by parts but am not sure. <br><br>Integral of&nbsp; x^2e^(-kx)&nbsp; with limits 0 to positive infinity. Thanks!!! <br>

did u mean this?

$\int_0^\infty x^2e^{-kx}dx$

use integration by parts twice..
• Nov 10th 2007, 01:11 AM
clipperdude21
would u=x^2 and dv= the rest for the 1st? Im lost with calculus lol
• Nov 10th 2007, 01:37 AM
kalagota
Quote:

Originally Posted by clipperdude21
would u=x^2 and dv= the rest for the 1st? Im lost with calculus lol

yes..