# Integral problem, does b & a change sometime in the problem?

1. Aug 23, 2009

### pillar

Problem number 16
http://img29.imageshack.us/img29/3179/38653938.png [Broken]
For the record the y at the end is cubed. Thanks in advance.

Last edited by a moderator: May 4, 2017
2. Aug 23, 2009

### snipez90

If you are referring to the limits of integration, then yes they change if you make the proper substitution that makes this integral very easy.

3. Aug 23, 2009

### Feldoh

What do you mean by: "do b and a change sometime?" Are you talking about the limits of integration changing?

4. Aug 23, 2009

### pillar

Yes the bounds or limits. b=2 and a=0 Why do they change to other numbers later on during the problem?

5. Aug 23, 2009

### zcd

If you substitute, for example, $$u=1+y^3$$, then the limits will change from ya=0, yb=2 to ua=1 and ub=9. That's because you're integrating with respect to u instead of y.