EquationTrekker for system of two 1st order ODEs

*To*: mathgroup at smc.vnet.net*Subject*: [mg109381] EquationTrekker for system of two 1st order ODEs*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 24 Apr 2010 04:02:01 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*Reply-to*: murray at math.umass.edu

Is it possible to use the EquationTrekker package to plot solutions of a system of two first-order ODEs? With Mathematica 7.0.1, I try: <<EquationTrekker` EquationTrekker[ {x'[t] == 2 x[t] + 3 y[t], y'[t] == x[t] - y[t]}, {x, y}, {t, 0, 20}, PlotRange -> {{-5, 5}, {-5, 5}}] Up pops the expected EquationTrekker graphics window. And if I then right-click somewhere in the xy-plane there, sometimes nothing happens and sometimes I get a point. (Except for the origin, which is an equilibrium point, all other trajectories for that system are either half-lines or hyperbolic arcs.) Note that the output from evaluating "?EquationTrekker" includes the following: "EquationTrekker[eqns,{x,y},{t,Subscript[t, min],Subscript[t, max]}] opens a graphical interface for specifying initial conditions and plotting the resulting numerical solution to the system of two first order ordinary differential equations eqns for the functions x and y" -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305