Electric potential from a uniformly charged rod at two points

[mr.alhassan]

Homework Statement

The image related with this problem is attached.
Electric charge is distributed uniformly along a thin rod of length a. with total charge Q. Take the potential to be zero at infinity. Find the potential at the following points (a) point P, a distance x to the right of the rod, and (b) point R, a distance y above the right-hand end of the rod. (c) In parts (a) and (b), what does your result reduce to as x or y become much larger than a?

Homework Equations

V = (9.0(10^9) * integral(dQ/r)

The Attempt at a Solution

I have no idea how to solve it.

 

[ehild]

Try to show some attempt. What is r?

ehild