dearcia

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These are questions asked by dearcia

Good afternoon everybody,

I am a beginer user in maple and I am having problems to plot a system of differential equations. My code is

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restart; with(VectorCalculus); with(LinearAlgebra); with(DEtools);
> p := 2*u*x*y^2; q := (x-1)/x;
> doth := simplify(-(sqrt(6)*x^3*(y-1)^2+u*((3+sqrt(6))*x^3*(y-1)^2+3*y^2-9*x*y^2+3*x^2*(y^2+2*y-1)))/p); ddotphi := simplify((y-1)*(sqrt(6)*x*y^2*(x-1)+u*(3*y^2-(6+sqrt(6))*x*y^2+x^2*((3+sqrt(6))*y^2+6*y-3)))/p);

>ode1 := diff(x(t), t) = x(t)*(1-x(t))*doth-x(t)^2*ddotphi/sqrt(6); ode2 := diff(y(t), t) = y(t)*(y(t)-1)*doth; ode3 := diff(u(t), t) = sqrt(3/2)*u(t)*(1+u(t))*q;

>DEplot3d([ode1, ode2, ode3], [x(t), y(t), u(t)], t = -2 .. 2, x = 0 .. 1, y = 0 .. 1, u = -1 .. 0, [[x(0) = .9, y(0) = .25, u(0) = -.95], [x(0) = .9, y(0) = .25, u(0) = -.5], [x(0) = .85, y(0) = .2, u(0) = -.15], [x(0) = .25, y(0) = .5, u(0) = -.5], [x(0) = .7, y(0) = .5, u(0) = -.6]], linecolor = [red, green, black, navy, maroon], thickness = 2, axes = boxed, labels = [x(t), y(t), u(t)], arrows = medium, stepsize = 0.1e-1, orientation = [30, 65]);

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and the next error appears

Error, (in DEtools/DEplot/direction3d) unable to store 'HFloat(HFloat(undefined))+HFloat(HFloat(undefined))*I' when datatype=float[8]

 

I have no idea what to do, and searching for solutions I have only found things that I dont understand.

 

Thank you very much in advance

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