Well this would mean that C_n{} and B_n{} would have to be zero if at infinity the potential can only be finite. That certainly makes solving for A_n{} and B_n{} easier since D_n{} can just collapse into them. For those two the boundary condition at V(R,phi)=0 would probably suffice.
As for...
Homework Statement
Find the potential outside of a long grounded conducting cylindrical rod of radius
R placed perpendicular to a uniform electric field E0.
Homework Equations
V(s,\phi) = a_{0}+b_0{}ln(s) + \sum(A_n{}cos(n\phi)+B_n{}sin(n\phi))*(C_n{}s^n{}+D_n{}s^{-n})
The sum being...