<< Getting all solutions from DSolve >>

*To*: mathgroup at smc.vnet.net*Subject*: [mg85880] << Getting all solutions from DSolve >>*From*: "Hatuey Hack" <hatuey.hack at gmail.com>*Date*: Tue, 26 Feb 2008 07:49:47 -0500 (EST)

Hello, I am trying to solve a diffusion problem using the following equation (in cylindrical coordinates): DSolve[J + D*Laplacian[ns[Rr]] - ns[Rr]/\[Tau] == 0, ns, Rr] The solution published in a scientific journal paper was: Paper = J*\[Tau] + BesselI[0, Rr/Sqrt[D/\[Tau]]]*C[1] + BesselK[0, Rr/Sqrt[D/\[Tau]]]*C[2] The solution from DSolve was: My = J*\[Tau] + BesselI[0, Rr/Sqrt[D/\[Tau]]]*C[1] + BesselY[0, -I*Rr/Sqrt[D/\[Tau]])]*C[2] So, the two solutions are very different, one is a real function (Paper) and the other one is a complex function (My). I would like to know how can I "force" DSolve to give me all the possible solutions or at less a constrained solution (something like give me only the real ones). My system: Mathematica 6, Linux Thanks in advance. Hatuey