# Homework Help: Bizarre integral!

1. May 18, 2010

### Bigfoots mum

Now then, im close to shedding a tear with this one.

This integral has been popping up in a few electromag examples iv been doing and i have absolutely no idea whats going on here.

The integral is 1/[(x2+z2)3/2] with respect to x

According to the textbook the answer is x/[z2(x2+z2)1/2]

I initially, without evening really thinking, went straight for -1/(x[x2+z2]1/2)

Any ideas?
Thanks

2. May 18, 2010

### Cyosis

Use the substitution $x=z \tan u$.

3. May 18, 2010

### annoymage

btw, you left a constant