Re: DSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg18757] Re: [mg18738] DSolve
- From: BobHanlon at aol.com
- Date: Tue, 20 Jul 1999 01:33:22 -0400
- Sender: owner-wri-mathgroup at wolfram.com
On version 4 for a Power Macintosh the DSolve returned unevaluated after a
few seconds.
I also verified your stated solution and boundary values as valid.
Bob Hanlon
In a message dated 7/17/99 5:28:17 AM, shamsundar at uh.edu writes:
>Here is a pair of differential equations that Version 3 could not solve
>
>(actually, it was still trying after 15 minutes on a 400 MHz PII!)
>
>w:=Exp[-a x];
>DSolve[{u'[x]==-u[x]+v[x]+w (1-a)+Cos[Pi x]-(1+Pi) Sin[Pi x],
> v''''[x]==u[x]+v[x]+(Pi^4-1) Sin[Pi x]-Cos[Pi x]-w, u[0]==2,
> v[0]==0,v''[0]==0,v[1]==0,v''[1]==0},
> {u[x],v[x]},x]
>
>These are linear equations with constant coefficients, and the exact solution
>
>is
> u=w+cos(Pi x), v=sin(Pi x)
>
>I would appreciate someone running this calculation in Version 4.
>