Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

<< 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



  • Prev by Date: Re: input style within a text style cell
  • Next by Date: Re: How to import a Matlab mat-file
  • Previous by thread: Re: Deleting elements from a Table
  • Next by thread: Re: << Getting all solutions from DSolve >>