Re: NDSolve with functions of vectors

*To*: mathgroup at smc.vnet.net*Subject*: [mg82990] Re: NDSolve with functions of vectors*From*: "Steve Luttrell" <steve at _removemefirst_luttrell.org.uk>*Date*: Tue, 6 Nov 2007 03:42:53 -0500 (EST)*References*: <fgca49$9ho$1@smc.vnet.net> <fgenik$fv6$1@smc.vnet.net> <fghb2n$i9j$1@smc.vnet.net>

Now I have had a look at my Messages window I see that I am getting the same warning messages as you. But the final result appears to be the correct solution to the differential equation. I have $Version = "6.0 for Microsoft Windows (32-bit) (April 20, 2007)". -- Steve Luttrell West Malvern, UK "Jerry" <JLK2941 at yahoo.com> wrote in message news:fghb2n$i9j$1 at smc.vnet.net... > Hi, I tried your code and got these errors. What did I miss? > Thanks. > > Part::partw: Part 2 of x[s] does not exist. >> > > Part::partw: Part 3 of x[s] does not exist. >> > > Steve Luttrell wrote: >> This does what you want: >> >> solution = >> NDSolve[{x'[s] == {2*x[s][[2]], x[s][[1]]/3, x[s][[3]]}, >> x[0] == {1, 1, 1}}, x[s], {s, 0, 1}] >> >> gives >> >> {{x[s]->InterpolatingFunction[{{0.,1.}},<>][s]}} >> >> Then >> >> ParametricPlot3D[Expand[x[s]/.solution[[1]]],{s,0,1}] >> >> gives a 3D plot of the trajectory for 0<=s<=1. >> >