MathGroup Archive 2004

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

Search the Archive

AW: "Rubbish" integration outputs

  • To: mathgroup at
  • Subject: [mg45730] AW: [mg45724] "Rubbish" integration outputs
  • From: Klamser at (Peter Klamser)
  • Date: Thu, 22 Jan 2004 03:37:31 -0500 (EST)
  • Sender: owner-wri-mathgroup at


the arbitrary variables k$XXXX are produced, because the result of your ODE
contains derivates of the e^x^2 function, Mathematica can not substitute
with Erf[x] neither integrate.

So you have to use a numerical solution with NDSolve.



-----Ursprüngliche Nachricht-----
Von: Iwonder [mailto:yssual at]
Gesendet: Mittwoch, 21. Januar 2004 10:55
An: mathgroup at
Betreff: [mg45724] "Rubbish" integration outputs


I always find me in troubles when integrating ODE that I think Mathematica
should be able to do. It's all right for the very simplest, but consider for
instance the following:

\!\(DSolve[\((x + 2  x\^2 + x\^3)\) \(y'\)[x] + \(x\^2\) \(y''\)[x] == A, y,

'A' a constant. Well, the problem is that I don't even the clue that
Mathematica *cannot* integrate it, there is some output with gibberish, like
K$14646 and the like (those are intermediary variables I guess). So what is
wrong? Is Mathematica expected to return such outputs?


  • Prev by Date: Re: "Rubbish" integration outputs
  • Next by Date: Trivial Fourier Transform Question
  • Previous by thread: RE: FORTRAN Question.
  • Next by thread: Trivial Fourier Transform Question