ParametricPlot Problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg54217] ParametricPlot Problem*From*: "James" <cannonjunk at hotmail.com>*Date*: Sun, 13 Feb 2005 22:17:04 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, I'm trying to do a Parametric Plot of a 2nd order differential equation: 1. dee = x''[t] + 0.5 x'[t] + x[t] + 0.1 x[t]^2 == Sin[0.1t]; 2. constraints = { x[0] == 1, x'[0] == 0}; 3. sol = NDSolve[ {dee, constraints}, x[t], {t, 0, 400} ]; 4. ParametricPlot[ {Evaluate[ x[t] /. sol], y [t]}, {t, 0, 200}] but it keeps telling me "ParametricPlot::pptr: "\!\({Evaluate[x[t] /. \[InvisibleSpace]sol]}\) does \ not evaluate to a pair of real numbers at t = 8.333333333333334`*^-6." etc. This is despite the fact that it works if I do a straight "Plot" (ie, I just remove the "Parametric" part of 4.) If anyone can suggest how I might correct this problem I would appreciate it a lot since I'm quite out of ideas. Thanks, James -- Mathematica 5.0 UK

**Follow-Ups**:**Re: ParametricPlot Problem***From:*DrBob <drbob@bigfoot.com>