Electric Potential: Find Potential Everywhere with q and -q on Z-Axis

[Crazy Gnome]

1. Homework Statement
Two point charges q and -q are located on the z axis at (x,y,z) = (0,0,a) and (0,0,-a) respectively.

Find the potential \phi everywhere



3. The Attempt at a Solution

I know all the equations and such, I just don't know how to integrate it. I am guessing that it is in cylindrical coordinates.

 

[bdforbes]

I don't think cylindrical coordinates or integration will be necessary. What is the formula for the potential due to a point charge? And are you familiar with the principle of superposition?