Working out formula for cylindrical capacitor

[funnyguy]

Homework Statement

Find the potential of a cylindrical capacitor
Radius of both cylinder plates, x and y where x<y
Height of the cylinder: h
Charge on the plates: q

Homework Equations

$$E = \frac{q}{A\epsilon_0} = \frac{q}{2\pi r h \epsilon_0}$$
$$\Delta V = \frac{\Delta U}{q} = - \int_a^b E dr$$

The Attempt at a Solution

$$V_y = \int_a^b E dr = \frac{q}{2\pi h \epsilon_0} \int_x^y \frac{1}{r} dr$$

Am I setting this up correctly?

 

[gneill]

Have a look http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capcyl.html#c2".