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
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