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Re: A "singular" equation

  • To: mathgroup at
  • Subject: [mg14760] Re: A "singular" equation
  • From: weber at (Matthias Weber)
  • Date: Sat, 14 Nov 1998 03:07:52 -0500
  • Organization: RHRZ - University of Bonn (Germany)
  • References: <72bf2q$> <72e2ng$>
  • Sender: owner-wri-mathgroup at

In article <72e2ng$oi0 at>, "W. K. Bertram" <wkb at>

> David Withoff wrote:
> > This worked ok for me.  Check with Wolfram Research tech support. Maybe
> > you have a corrupted/old/etc copy of Mathematica.
> >
> > % math
> > Mathematica 3.0 for Solaris
> > Copyright 1988-97 Wolfram Research, Inc.
> >  -- Terminal graphics initialized --
> >
> > In[1]:= DSolve[(1-x^2)y'[x]^2==(1-y[x]^2),y[x],x]
> >
> >                                  2          2              2      2
> >                   x - Sqrt[-1 + x ] + x C[1]  + Sqrt[-1 + x ] C[1]
> > Out[1]= {{y[x] -> -------------------------------------------------}}
> >                                        2 C[1]
> >
> >
> Dear David,
> I have exactly the same problem on my system as the previous writer. I'm
> running Mathematica version 3.0.0 on a 200Mhz Pentium Pro under Windows
> 95. When I try to execute the above command I get a "This program has
> performed an illegal operation ..." message and the notebook freezes
> up. Is this a feature of this particular verion of  Mathematica? If so,
> maybe Wolfram might consider offering its affected customers an upgrade
> to a more recent version  at a much better rate than the A$700 - A$800
> price that was quoted to me for an upgrade from version 3.0.0 to 3.0.1.
> Cheers,
>    Bill Bertram

I agree with Bill. However, Mathematica 3.0.0 has quite a lot bugs like
this (just browse through the newsgroup archives), and it if Wolfram
would be willing to fix them all for free, this would keep them busy
for years without payment...

We all are interested in a stable and reliable symbolic and numeric 
("integrated " ?) tool, and I would appreciate if Wolfram would accept
more feedback from customers. I spent a lot of time locating 
reproducible bugs and reporting them carefully. In many cases I got
helpful response, sometimes the bug was acknowledged, and only once I
was told to download a bug-fix for our Irix, for which we have the
so-called premium-service (when you subscribe, you are told that you
are will get all updates freely, but I was not expecting that I have to
report the bug for it). The worst kind of answer you can get is "Yep,
that's a known bug, but look, our development version 8.5 handles it

My suggestion would be  that there should be a public beta cycle for
educational institutions so that Mathematica can be tested by people
who really use the appraised mathematical features, with the offer of
acceptable rebates for reported bugs. Well, this is probably too much
to hope for.

Matthias Weber

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