Quick integrating question (part of a series question)

1. Nov 14, 2007

quickclick330

Quick integrating question....(part of a series question)

Still studying for my exam...

Came across this example and I don't know what the method is for integrating this type of problem? (I'm using it to do the integral test for series). How did they get rid of the x^3? thanks for the help :-)

2. Nov 14, 2007

ZioX

Well what's the derivative of -1/3 * exp(-x^3)?

3. Nov 14, 2007

HallsofIvy

Staff Emeritus
Or: let u= x2 so that du= 3x2 dx.

4. Nov 14, 2007

quickclick330

ahhh...i see it now. thanks :-)