NDSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg42880] NDSolve
- From: "Steffen" <nnnx at gmx.de>
- Date: Fri, 1 Aug 2003 01:25:50 -0400 (EDT)
- Organization: University of Karlsruhe, Germany
- Sender: owner-wri-mathgroup at wolfram.com
Hi all,
unfortunately Mathematica is not able to solve the following:
NDSolve[{
y1'[x] == -k1 y1[x] y2[x] + km1 y3[x],
y2'[x] == -k1 y1[x] y2[x] + km1 y3[x],
y3'[x] == k1 y1[x] y2[x] + km2 y4[x] M - (km1 + k2 M) y3[x],
y4'[x] == -km2 M y4[x] + k2 M y3[x],
y1[0] = 10^13,
y2[0] = 10^16,
y3[0] = 0,
y4[0] = 0,
} , {y1 , y2 , y3 , y4} , {x , 0 , 50 10^-6}]
This is a differential equation system for a kinetical system ( y1 + y2 <=>
y3 , y3 <=> y4). Only y1 and y2 exsists in the beginning. The constants k1,
km1, k2, km2 and M are numbers and are defined above.
Mathematica gives an error: " NDSolve::ndnef : The number of differential
equations (3) is not equal to the number of the initial conditions (1)."
But I did gave him all the initial conditions, did´nt I? By the way there
are 4 eq. and 4 conditions.
I am sorry for this probably easy prob. I looked in Mathematica Help, in
this forum and at Wolframs MathSource Webpage. I did not find anything for
helping me to solve this Prob. This means, that I am making a very stupid
mistake, but I do not know, which one. Can please anybody help me?
Thanks a lot
Steffen Nasterlack
University of Karlsruhe
Germany
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