Re: Problem with Differential Eq

• To: mathgroup at smc.vnet.net
• Subject: [mg82587] Re: Problem with Differential Eq
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 25 Oct 2007 06:12:13 -0400 (EDT)
• Organization: Uni Leipzig
• References: <ffn068\$5m2\$1@smc.vnet.net>

```Hi,

you miss a comma

solution =
NDSolve[{lpmk1'[
t] == (lpmk10[lpv[t]] - lpmk1[t])*(1/lptaumk1[lpv[t]]),
lpmk1[0] == lpmk10[-80]*(1/lptaumk1[-80]),
lpv'[t] == -1*(+1*125*(lpmk1[t] 4)*(lpv[t] + 80)),
lpv[0] == -80}, {lpv, lpmk1}, {t, 0, 1500}, Method -> Automatic];
ParametricPlot[Evaluate[{t, lpv[t]} /. solution], {t, 0, 1500},
PlotPoints -> 1500, PlotRange -> All]

may work.

Regards
Jens

Dave wrote:
> The following .nb file just won't run!!! I can't see what is wrong as it is
> a relativly simple series of self evaluating differential equations.
>
> [code]
>
> lpmk10[u_] := 1/(1 + Exp[(u + 12.3)/-11.8]);
> lptaumk1[u_] := 14.4 - 12.8/(1 + Exp[(u + 28.3)/-19.2]);
>
> solution =
> NDSolve[{lpmk1'[t] == (lpmk10[lpv[t]] - lpmk1[t])*(1/lptaumk1[lpv[t]]),
> lpmk1[0] == lpmk10[-80]*(1/lptaumk1[-80])
> lpv'[t] ==
> -1*(+1*125*(lpmk1[t]^4)*(lpv[t] + 80)),
> lpv[0] == -80},
> {lpv, lpmk1}, {t, 0, 1500}, Method -> Automatic];
> ParametricPlot[Evaluate[{t, lpv[t]} /. solution], {t, 0, 1500},
> PlotPoints -> 1500, PlotRange -> All];
>
>
>
> [/code]
>
>
>
> if any one can shed some light on this it would be great
>
>
>

```

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