Problem with Differential Eq
- To: mathgroup at smc.vnet.net
- Subject: [mg82544] Problem with Differential Eq
- From: "Dave" <david.fourie at ncl.ac.uk>
- Date: Wed, 24 Oct 2007 04:27:48 -0400 (EDT)
- Organization: Newcastle University
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