This sometimes works
(%i19) expr:x/(x^2-4);
(out19) x/(x^2-4)
(%i20) solve(1/expr=0,x);
(out20) [x = -2,x = 2]
Rich
--------------------------------------------------
From: "John Lapeyre" <pdl at johnlapeyre.com>
Sent: Wednesday, May 26, 2010 8:08 AM
To: <maxima at math.utexas.edu>
Subject: detecting singularity
> Hi,
>
> Is there a way to detect a division by zero without causing
> an error that returns to the maxima toplevel? It would be
> useful, for instance to check for singularities at endpoints
> of a numerical integration range. (Something like perl's
> eval() would be great! For instance with parse_string() to
> test if a string is legal maxima without causing an
> exception.)
>
> A harder question is to search for singularities (including
> removable singularities) within a range. In numerical
> integration, Mathematica requires a user to list
> singularites in the interior of the interval, something that
> RJF criticized 19 years ago, but is still the case. But
> there must exist algorithms to search for them.
>
> Regards,
> John
>
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