NDSolve and Lane-Emden
- To: mathgroup at smc.vnet.net
- Subject: [mg42512] NDSolve and Lane-Emden
- From: fedgingt at fandm.edu
- Date: Sat, 12 Jul 2003 05:19:11 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi. I have not worked extensively with Mathematica in the past. I am working
with the Lane-Emden equation for a polytropic gas:
-y[x]^N=1/x^2*D[x^2D[y[x],x],x]. N is the polytropic index. I have been using
NDSolve to find a solution to this equation when N=3.3, 3.35 and 3.4 for x
starting a 1. However, I am have trouble with the InterpolatingFunction
Mathematica gives me. It does not give numerical answers (for example, when I
type y[2]/.% the output Mathematica gives is {y[2]}.) At the same time, I am
able to plot this function. Is there some way to get a result for the
Lane-Emden that will produce numerical answers? Thanks, Fred