Re: Phase Plot of Simple Harmonic Motion using Mathematica ??

*To*: mathgroup at smc.vnet.net*Subject*: [mg126510] Re: Phase Plot of Simple Harmonic Motion using Mathematica ??*From*: Christoph Lhotka <christoph.lhotka at fundp.ac.be>*Date*: Wed, 16 May 2012 04:21:54 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Dear Rahul, this makes your code work: replace in your expression \[RightArrow] by \[Rule] (delete the arrows and retype them properly). If you look on the documentation for \[RightArrow] you will find that it has no built-in meaning and that it can be entered as [ESC]_->[ESC], where _ stands for an extra space, while \[Rule] is entered as [ESC]->[ESC] only. In the email text it is easy to see the difference between \[RightArrow] and \[Rule], to see the difference in your notebook just press Shift+Ctrl+E inside the cell or use Hold[expr]//FullForm to see the unevaluated fullform of the expression. Best, Christoph Addendum: another issue is, that the error messages of the present example are not really related to the problem, does anyone know why? On 05/15/2012 10:54 AM, Rahul Chakraborty wrote: > Hi all, > > Plz check my code below for Phase plot of Simple Harmonic motion. The output should be a circle with x along X-axis and dxdt along y-axis. > > I'm not getting the output. kindly let me know where i'm wrong. > > Clear[k, m]; > k = 1; > m = 3; > solution = > NDSolve[{x''[t] + k/m x[t] == 0, x[0] == 5, x'[0] == 0}, > x, {t, 0, 250}, MaxSteps \[RightArrow] 50000, > WorkingPrecision \[RightArrow] 25] > ParametricPlot[Evaluate[{x[t], x'[t]} /. solution], {t, 0, 100}, > PlotRange \[RightArrow] All, > AxesLabel -> {"x", "\!\(\*OverscriptBox[\(x\), \(.\)]\)"}] > > > Following are the errors: > > 1)NDSolve::dvlen: The function x[t] does not have the same number of arguments as independent variables (3).>> > > 2)ReplaceAll::reps: {NDSolve[{x[t]/3+(x^\[Prime]\[Prime])[t]==0,x[0]==5,(x^\[Prime])[0]==0},x,{t,0,250},MaxSteps\[RightArrow]50000,WorkingPrecision\[RightArrow]25]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.>> > > 3)ParametricPlot::pllim: Range specification PlotRange\[RightArrow]All is not of the form {x, xmin, xmax}.>> > > > Regards, > > rc >