Iterative procedure for potential distribution of a cylindrical problem?

[OneMoreName]

Hi there,

I arrived at the solution for a electric potential problem for a semi-infinite cylinder (there was a potential distribution given for the boundary conditions but that's not important here).

http://i210.photobucket.com/albums/bb283/DidgeFrank/Cylinder_pot.jpg

The solution is equation (1). You have to use the Bessel functions of first order and there is a parameter λ_n appearing (equation (2)). My problem is how to calculate the various λ_n values. I know it must work with an iterative procedure. I am especially interested in a Mathematica procedure to do this.

Thanks in advance for some helpful hints,
OMN

 

[OneMoreName]

Solved.