1. ## Definite integral help please!

Can somebody help me in telling me how to solve the following integral?

$\int\limits_0^a \frac{1}{(x^2+z^2)^\frac{3}{2}}dx$

I'm quite at a loss...

2. Use the trig sub:

Let x = ztan(t)

dx = z sec^2(t)dt

You'll get a simple integral of cos(t)