Integrate Equations: Basic Steps for (x^2+y^2)^-1/2 dx

[Unto]

How do I integrate equations such as:

(x^2 + y^2)^-1/2 dx

?

I've completely forgotten and I'm in Uni at the moment. I was answering a question on find the electric field of a charged rod and I couldn't finish it because I didn't know how to integrate something like this.

 

[Mark44]

First off, that's not an equation. An equation always has = somewhere in the middle.

The usual approach for this type of integral is trig substitution, with tan w = x/y, sec^2(w)dw = dx/y, and y sec(w) = sqrt(x^2 + y^2). (As far as the integration is concerned, y is considered to be a constant.)