I am a new member of this community (not newby, though, in Mathematica) and I came to this community with a question for which I could not find answer in the Internet.
Very often, during solution of PDE with 2 or more spatial variables in cylindrical or spherical coordinates, you end up with radial 1D ODE with ordinary (Dirichlet or Neumann) boundary condition at fixed radius r=R and requirement that the solution should be regular (non-diverging) at the origin r=0. Is there any way to set such regularity "boundary" condition at r=0 in DSolve? I put quotes because the origin is not a boundary and we cannot set a value of the solution (or its derivative) there. When I use Mathematica in the interactive mode, I can manually remove the divergent term from the solution, but I cannot write a script which can finish the job without human intervention. Any ideas? I use Mathematica 9.0.
It would help if you included samples of what you are trying to do. Example equations and what you have tried already.