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Differntial Equations

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  • Subject: [mg8015] Differntial Equations
  • From: Bernhard Petri <bernhard.petri at>
  • Date: Sat, 2 Aug 1997 22:32:26 -0400
  • Organization: Universitaet Regensburg
  • Sender: owner-wri-mathgroup at

I have a system of 2 Diff. Eqns. which describe an oscillating chemical

x'[t]==z (d-(x[t] y[t]/(y[t] (1+x[t])+a)))
y'[t]==(x[t] y[t]/(y[t] (1+x[t])+a))-b y[t]/(1+x[t])

for a=30; b=0.1; d=0.03; z=1/6; and x[0]==1, y[0] == 15;

I have tried to solve these with NDSolve. The system shows damped
oscillations. A permanent oscillation will be obtained by the additional
constraint that y[t] stays always above 0.00001. How can I include this
constraint into my system? Has anybody a practical suggestion?

Cheers Bernhard Petri
Bernhard Petri

Institut f=81r Zoologie 1
Universit=84t Regensburg
D-93040 Regensburg

Tel.: ++49/941/943-2156
Fax.: ++49/941/943-3304

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