Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1996
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1996

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: ODE

  • To: mathgroup at smc.vnet.net
  • Subject: [mg4187] Re: [mg4091] ODE
  • From: WOLKOWISKY JAY H <wolkowis at euclid.Colorado.EDU>
  • Date: Tue, 11 Jun 1996 00:54:57 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

>From: bob at zim.uoregon.edu (Robert Zimmerman)
>Subject: {mg4091] ODE
>Organization: University of Oregon

     While  lectureing with Mathematica I noticed that the following ODE   
does  not return the correct  initial conditions. 
    Is this an error or standard procedure?

 eq1=    {    x y'[x]+(x+2) y[x]==2  Exp[-x],  y[0]==y0};
 
 sol=    y[x]/.(eq1//  DSolve[#,y[x] ,x]&//Flatten)
 
 
 sol/.x->0       (*Should equal to y0 and not 1*)

Out[64]=      E^(-x)
Out[67]=        1     (*Should equal to y0 and not 1*)



The answer to your question is that x=0 is a singular point
of the ODE, and so you can not specify arbitrary initial
conditions.

I hope this helps.

Jay H. Wolkowisky

==== [MESSAGE SEPARATOR] ====


  • Prev by Date: Re: The Mathematica Journal-Supplements
  • Next by Date: Mathematica graphics into TeX
  • Previous by thread: Langauge L to Mathemtaica ?
  • Next by thread: Mathematica graphics into TeX