List Archives >
Maple User Group List Archive >
Archive by date >
This Month By Date >
This Month By Topic
[MUG] Re: ODE with singularity
| [MUG] Re: ODE with singularity |
|
Author: Maple User Group
Posted: Fri, 22 Nov 2002 16:40:22 -0500
|
>> From: Maple User Group "maple_gr"
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Date: Tue, 19 Nov 2002 17:05:58 -0800
To: "maple-list"
From: David Harrington "dharr"
Subject: ODE with singularity
At 01:16 PM 11/18/2002 +0100, you wrote:
>there is a warning and i'm interested in this number. is there a way
>to assign the singularity ( here eta=0.11473470 ) to some placeholder?
>for example Sing:=0.11473470, without doing it by hand. something like
>grep it
you can get at the warning string with lastexception, e.g.,
print(lastexception);
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
From: "Ivan Huerta" "ihuerta"
To: "maple-list"
Subject: ODE with singularity
Date: Wed, 20 Nov 2002 10:17:02 -0400
Hi:
You can get the exact value of the singularity, which is
Sing:= alpha+1-1/3*sqrt(9*alpha^2+18*alpha+6)
as follows (This is Maple 6.01)
>ode256:=(1+3*alpha)/6*diff(diff(xi(eta),eta),eta)/(1+diff(xi(eta),eta)^2)^(
3/2)+1+alpha-eta=0:
> ic256:=xi(1)=0,D(xi)(1)=-N;
> p:=dsolve({ode256,ic256},xi(eta));
> sol1:= subs(p,xi(eta));
> dsol1:= diff( sol1,eta);
> L:=limit(dsol1,N=infinity); temp:=op(L);
> 1/temp[4]; factor(%); solve(%=0,eta); evalf( map2(subs,alpha=0.51,[%]));
Regards,
Prof. Ivan Huerta
Facultad de Matematicas
Pontificia Universidad Catolica de Chile
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Date: Wed, 20 Nov 2002 19:11:07 -0400
From: C W "sylvester7"
To: "maple-list"
Subject: ODE with singularity
Hi !
The following is not about the singularity, but if :
alpha=0.51 and D(xi)(1)=-100000 then
xi(eta) is real valued for eta=0.2 .. 1.0 only.
Chris
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Date: Wed, 20 Nov 2002 19:20:15 -0400
From: C W "sylvester7"
To: "maple-list"
Subject: ODE with singularity
Hi again !
It also appear that one may solve, this system, without approximating -infinity.
Chris
|
[View Complete Thread]
Previous by date: [MUG] Re: coeff on a generic polynomial, Maple User Group
Next by date: [MUG] Re: animation problems, Maple User Group
Previous thread: [MUG] more about implicitdiff:complexity and recursiveness, Charles James Leonardo Quarra Cappiello
Next thread: [MUG] animation problems, Bertfried Fauser
|
(NAG)
