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Kitonum — Fri, 08 Mar 2013 23:47:45 Z

To draw a phase curve, you must:

1) Set the value of the parameter k .
2) Specify the initial condition.

If you interested of changing of the curve in response to changes k , you can make animation with the parameter k .

Example (for greater clarity, the ranges of k and t are reduced):

with(DEtools):
for k from 1 to 2 by 0.01 do
DE := diff(x(t), t) = x(t):
DF := diff(y(t), t) = k*y(t):
A[k]:=phaseportrait([DE, DF], [y, x], t = 0 .. 0.5, [[y(0)=1, x(0)=1]], color=black, linecolor = red):
od:
plots[display](seq(A[k], k=1..2, 0.01), insequence=true);

MaplePrimes - answers and comments on Question, How to draw a phase curve of ODE system?

Re