# Indefinite Integral

1. Dec 4, 2011

### JimmyCat

I'm having a problem with the following integral: x^3/sqrt[1 + x^2] dx

Can this be done with substitution or integration by parts?
Throw me some hints at this one please!

Sorry I forgot to include my attempt.

I tried solving this by substitution, letting u=1-x^2. Then letting (-1/2)du = xdx. Simplifying it down and came to the answer of 1/3(1-x^2)-sqrt(1-x^2) + C

Last edited: Dec 4, 2011
2. Dec 4, 2011

### micromass

Staff Emeritus
Please make an attempt at the solution, or this thread will be deleted.