Predator-Prey Problems

Applications of Systems of Differential Equations

(continued from last page...)

The two command sequence that you just entered should have gone like this:

rabfox2=
NDSolve[{r'[t]==2r[t]-0.01 r[t] f[t],
   f'[t]==-f[t]+0.01 r[t] f[t],
   r[0]==150,f[0]==200},{r[t],f[t]},
   {t,0,10}]

Solution Part 1
Solution Part 2

rabfoxplot2=
ParametricPlot[{rabfox2[[1,1,2]],
   rabfox2[[1,2,2]]},
   {t,0,10}]

Phase Plot

It looks like the new initial conditions also generated a stable orbit, but not of quite the same shape as the last one we made.

Carefully read the command sequence over again. You are about to go through a set of exercises which are almost identical to the one we just did. You can always come back to this page later if you need to use it as a reference.

Anyway, let's move on to the exercises...

$Compass$

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