khoirun

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10 years, 81 days

MaplePrimes Activity


These are replies submitted by khoirun

@Preben Alsholm thanks a lot, it really solved, i used to maple 12 before.

@Carl Love 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]);

@Carl Love i m really sorry for asking a lot. the fomula by  Doug Meade 2622  was successful, but when i tried to my my system there was a warning said " cannot evaluate the solution further right of .73473335, probably a singularity"

@Carl Love you helped me a lot, thank you very much.

@Doug Meade thank you vary much it helped me alot. but the formula to combining two plots for both the phase protrait and the trajectory can't run, the warning is " Error, (in plots:-display) expecting plot structure but received: ODEplot3d([diff(x(t), t) = 2*y(t), diff(y(t), t) = 2*x(t)-y(t), diff(z(t), t) = 1], [x(t), y(t), z(t)], t = -1 .. 1, [[x(0) = 0, y(0) = .5, z(0) = 0], [x(0) = 0, y(0) = 1, z(0) = 0], [x(0) = 0, y(0) = -.5, z(0) = 0], [x(0) = 0, y(0) = -1, z(0) = 0]], stepsize = .2, linecolor = blue, axes = boxed)"

 

Thanks and Regards

 

khoirun

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