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>*Reply-to*: kuska at informatik.uni-leipzig.de

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 > > >