       Re: NDsolve question

• To: mathgroup at smc.vnet.net
• Subject: [mg29138] Re: NDsolve question
• From: Erich Mueller <emuelle1 at uiuc.edu>
• Date: Wed, 30 May 2001 23:28:25 -0400 (EDT)
• Organization: University of Illinois at Urbana-Champaign
• References: <9f2gjo\$881\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Mathematica is case sensitive.  You used lower case letters in defining

Erich

On Wed, 30 May 2001, Supriyo Sinha wrote:

>
> Hi,
>
> I'm relatively new to Mathematica, but I heard
> that Mathematica is better at solving differential equations.  Anyways,
> I'm trying to solve a set of six coupled differential equations (each
> equation is coupled to a maximum of two other equations).  When I try to
> evaluation, I get the following error message:
>
> NDSolve::ndnum: Differential equation does not evaluate to a number at Z =
> 0..
>
> The code I'm trying to run is the following:
>
> Betapump = 2.23038
> Beta1 = 2.0744
> Beta2 = 1.92669
> Beta3 = 1.78431
> Beta4 = 1.66273
> Beta5 = 1.54011
> g1 = 0.97536
> g2 = 0.95079
> g3 = 0.92583
> g4 = 0.90336
> g5 = 0.87948
> NDSolve[{Kp'[Z] == -1*K1[Z]*Kp[Z] - Betapump*Kp[Z],Kp == 1,K1'[Z] ==
> G1*(K1[Z]*Kp[Z]-K1[Z]*K2[Z])-Beta1*K1[Z],K1 == (0.1)^12,K2'[Z] ==
> G2*(K2[Z]*K1[Z]-K2[Z]*K3[Z])-Beta2*K2[Z],K2 == (0.1)^12,K3'[Z] ==
> G3*(K3[Z]*K2[Z]-K3[Z]*K4[Z])-Beta3*K3[Z],K3 == (0.1)^12,K4'[Z] ==
> G4*(K4[Z]*K3[Z]-K4[Z]*K5[Z])-Beta4*K4[Z],K4 == (0.1)^12,K5'[Z] ==
> G5*(K5[Z]*K4[Z])-Beta5*K5[Z],K5 == (0.1)^12},{Kp[Z], K1[Z], K2[Z],
> K3[Z], K4[Z], K5[Z]}, {Z, 0, 500}]
>
> All the equations are pretty similar.  I would actually prefer to use
> DSolve to get an equation, but I will settle for the interpolated solution
> given by NDSolve and plot it.
>
> Any help would be GREATLY appreciated.
>
> Thanks,
> Supriyo
> supriyo at stanford.edu
>
> ---------------------------------------------------------------------
> "The presence of an enthusiast makes me as cold as ice, while I think
> I should become passionately excited if I had much to do with a dull
> and phlegmatic person."
>
> 			- Gregory Aleksandrovich Pechorin
> 			  M. L. Lermontov's A Hero of Our Own Times
>
> "...the only consolation you have left is to whip yourself..."
>
> 			- F. Dostoyevsky's Notes From the Underground
>
>
>

```

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