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How plot phase portrait on a cylinder?...

Fata123 10 Maple
differential-equations cylinder phaseportrait
October 17 2017
2 3

How to plot phase portrait on a cylinder for The Lotka–Volterra equations (for some definite α, β, γ, δ):

{\begin{aligned}{\frac {dx}{dt}}&=\alpha x-\beta xy\\[6pt]{\frac {dy}{dt}}&=\delta xy-\gamma y\end{aligned}}

 

 

Error in DEplot3D...

Fata123 10 Maple
syntax deplot3d
October 17 2017
1 0

I have a ploblem here:

plots[changecoords](subs(CURVELIST = CURVES, DEplot3d({(diff(rho(t), t))*(cos(varphi))(t)+rho(t)*(diff((cos(varphi))(t), t)) = 0.1*rho(t)*(cos(varphi))(t)-0.8e-4*rho(t)^2*(cos(varphi))(t)*(sin(varphi))(t), (diff(rho(t), t))*(sin(varphi))(t)+rho(t)*(diff((sin(varphi))(t), t)) = 0.4e-4*rho(t)^2*(cos(varphi))(t)*(sin(varphi))(t)-0.4e-1*rho(t)*(sin(varphi))(t)}, [rho(t), varphi(t)], t = 0 .. 2*Pi, [[rho(0) = 1, varphi(0) = 0]], scene = [rho, varphi, t])), cylindrical);
Error, (in DEtools/DEplot/CheckDE) only derivatives of dependent variables can be present
 

Thank you for the help.

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