Deriving potential energy by simulation method

[aruwin]

The picture shows the potential due to ring charge.
Please show the full steps of deriving the equation of electrical potential. I don't know how to start at all.

NOTE:
The electric potential of the revolving symmetrical ring electric charge related to the axis z as depicted in the diagram 5.3, is also called a charged coil or a charged ring in the electromagnetism books, but most of the time, it gives an infinite series of equation that uses Legendre function. It is commonplace to use complete circle integral function in the charge simulation method. If the position (height) of ring electric charge is Z, the diameter is R, and the charge density is λ, the electric potential of the point P will be as represented in the next equation.

In the equation, l is the distance between the part of the ring charge dθ and P.

 

[I like Serena]

Hi aruwin!

I may be a bit late, but if you're still interested...

What would the cartesian coordinates of a point on the ring be?

If you have that you can find the cartesian distance $l$ between the 2 points and substitute it in the formula that is given.