Teacode.com: Maple

Здравствуйте, Марина. Если речь идет об экономической модели, то синтаксис следующий:Пусть k=0.3, m=0.1, a=20, c=-10, q0=20, s0=10, d0=50. with(DEtools); sys := diff(x(t), t) = 9*y(t)-12, diff(y(t), t) = -.1*x(t)+2; DEplot([sys], [x(t), y(t)], t = 0 .. 30, [[x(0) = 20, y(0) = 3], [x(0) = 19, y(0) = 2], [x(0) = 21, y(0) = 1]], stepsize = 0.05, linecolor = brown, arrows = LARGE, color = [-.1*(x(t)-20), .3*(30*y(t)-40), .1], title = `Economic model`);

Спасибо! пытаюсь построить кинетический портрет with(plots): odeplot(dsolve({diff(q(t),t)=0.3*((20*p(t)+10)-(50-10*p(t))),diff(p(t),t)=-0.1*(q(t)-20),q(0)=20,p(0)=3},[q(t),p(t)],type=numeric),color=green,0..30,numpoints=2000,thickness=2,stepsize=0.01,title='Economic model'); Не могу понять что не так..

with(plots); odeplot(dsolve({diff(p(t), t) = -.1*(q(t)-20), diff(q(t), t) = .3*(20*p(t)+10-50+10*p(t)), p(0) = 3, q(0) = 20}, [q(t), p(t)], type = numeric, method = classical), [[t, q(t)], [t, p(t)]], 0 .. 30, numpoints = 2000, thickness = 2, title = 'Economic*model')