       Re: adding subset of interpolating function from a system of ODE

• To: mathgroup at smc.vnet.net
• Subject: [mg45864] Re: adding subset of interpolating function from a system of ODE
• From: bobhanlon at aol.com (Bob Hanlon)
• Date: Wed, 28 Jan 2004 05:19:02 -0500 (EST)
• References: <bv5e79\$t28\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```solution=NDSolve[{
Derivative[x][t]==-y[t]-z[t],
x==-0.04,
Derivative[y][t]==x[t]+0.425*y[t],
y==-0.3,
Derivative[z][t]==2-(4-x[t])*z[t],
z==0.52},
{x[t],y[t],z[t]},{t,0,25}];

ParametricPlot3D[
Evaluate[{x[t],y[t],z[t]}/.solution],
{t,0,25},PlotPoints->1000,PlotRange->All];

Plot[x[t]+y[t] /. solution, {t,0,25}];

ParametricPlot[{y[t], x[t]+z[t]} /. solution,
{t, 0, 25}, PlotRange->All];

Bob Hanlon

In article <bv5e79\$t28\$1 at smc.vnet.net>, sean_incali at yahoo.com (sean kim) wrote:

<< Please consider the lorenz system for example.

In:=
solution=NDSolve[{Derivative[x][t]\[Equal]-y[t]-z[t],x\[Equal]-0.04,
Derivative[y][t]\[Equal]x[t]+0.425*y[t],y\[Equal]-0.3,
Derivative[z][t]\[Equal]2-(4-x[t])*z[t],z\[Equal]0.52},{x[t],
y[t],z[t]},{t,0,25}];

ParametricPlot3D[Evaluate[{x[t],y[t],z[t]}/.solution],{t,0,25},
PlotPoints -> 1000,PlotRange ->All];

above shows a parametric plot of x, y and z.

but let's say for some reason I want to plot the following..

x+y vs time
x+z vs  y

how do I achieve this?  is this possible in mathematica?

```

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