Hi everybody!

My problem is: I would like to draw a phase diagram for a system of 3 differential equations. So i followed maple's codes  posted here. It run successfully, but when i tried it to my own system there was a warning said " cannot evaluate the solution further right of .73473335, probably a singularity". Below is my maple code to my own problem. Really need your opinions.

my code:

> m := .18; A := .45; B := .3; C1 := .2; C2 := .14; MU := .5;

> SYS := [diff(x(t), t) = x(t)*(1-x(t)-m*y(t)), diff(y(t), t) = y(t)*(1-2*x(t)-y(t)+m*x(t)-A*z(t)/(B+y(t))-C1), diff(z(t), t) = z(t)*(MU*A*y(t)/(B+y(t))-C2)];

>
> IC := [[x(0) = .7, y(0) = .1, z(0) = .5], [x(0) = .8, y(0) = .2, z(0) = 0], [x(0) = .9, y(0) = .3, z(0) = 0], [x(0) = 1, y(0) = .4, z(0) = 0], [x(0) = .7, y(0) = .1, z(0) = .5], [x(0) = .8, y(0) = .2, z(0) = 0], [x(0) = .9, y(0) = .3, z(0) = 0], [x(0) = 1, y(0) = .4, z(0) = 0]];

> RHS := eval(map(rhs, SYS), [x(t) = x, y(t) = y, z(t) = z]);

> with(DEtools);
> p1 := fieldplot3d(RHS, x = 0 .. 1, y = 0 .. 1, z = 0 .. 1, grid = [10, 10, 10], axes = boxed);
> p2 := DEplot3d(SYS, [x(t), y(t), z(t)], t = -1 .. 1, IC, stepsize = .2, linecolor = blue, axes = boxed);
> display(p1, p2, view = [-1 .. 1, -1 .. 1, -1 .. 1]);

Thanks and regards

Khoirun

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