# Homework Help: Improper Integral

1. Apr 12, 2009

### Mathematics07

1. The problem statement, all variables and given/known data
The integral from -infinity to infinity of (2-x^4)dv

2. Relevant equations
U substitution

3. The attempt at a solution
Dont know what to use as my "u" ?

2. Apr 12, 2009

### n!kofeyn

You have a dv in your given integral. Is this the integral you mean?
$$\int_{-\infty}^\infty (2-x^4) \,dx$$
If so, you do not need u-substitution here. Also, to compute an improper integral of this form you need to evaluate:
$$\lim_{s\to\infty} \int_{-s}^s (2-x^4) \,dx$$

3. Apr 12, 2009

### Mathematics07

yes that the write integral . . so basically i just need to do regular anti derivate and then evaluate it ?

4. Apr 12, 2009

### Jay J

so for an example like this you would just do a regular anti derivative and then substitute your "s" in for the infinities and then evaluate >?

-Jay J-