Re: Coupled Differential Equations

• To: mathgroup at smc.vnet.net
• Subject: [mg34814] Re: Coupled Differential Equations
• From: shubi at nusun.jinr.ru (Nodar Shubitidze)
• Date: Sat, 8 Jun 2002 05:21:24 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```"Cyrill Slezak" <Cyrill.Slezak at Physik.Uni-Augsburg.DE> wrote in message news:<adkf9d\$9u8\$1 at smc.vnet.net>...
> I understand that NDSolve will solve a set of first order coupled. diff.eqn.
> Here is my problem: I have a set of 20+ equation that all have the exact
> same structure and I can't seem to find an easy way to input them. For any
> help I'd be highly appreciative. The equations are of the form
>
> d V_k(l)/d l = V_k(l) + Sum[ V_k'(l), (k not equal k')]
>
> where k is the number of diff. eqn.
>
> Thanks for any help,
>
> Cyrill

Hello,

You may write your system as:
d V_k(x) /d x = Sum[ V_m(x),{m=1,nmax}]
Then
d V_1(x)/d x  =d V_2(x)/d x  =d V_3(x)/d x  = . . .
and
V_2(x) = V_1(x) + C_2
V_3(x) = V_1(x) + C_3
. . .