# Homework Help: Can't do an integral

1. Oct 4, 2006

### alfredbester

p(r) is proportional too (1/r)Exp(-r/R). r is the variable.

I'm trying to normalise this function (R is proton radius), so I'm trying to get the integral between infinity and -infinity = 1 so I can find the normalisation constant. I don't know how to do this integral I've tried by parts but it seems there are discontuinities. I'm probably missing something obvious, can sombody point me on the right track?

Last edited: Oct 4, 2006
2. Oct 4, 2006

### Pyrrhus

Non-elementary solution.

http://mathworld.wolfram.com/ExponentialIntegral.html" [Broken]

Last edited by a moderator: May 2, 2017
3. Oct 4, 2006

### alfredbester

Thanks, I can't see how to normalise this function however.

4. Oct 4, 2006

### jpr0

Probably you're integrating from $r=0$ to $r=\infty$, not over the whole range of r.