Viktor T. Toth
vttoth at vttoth.com
Mon Jun 2 17:42:28 CDT 2008
It is difficult to discern the intent of the original e-mail clearly, but it
seemed to me that the poster was specifically referring to the behavior when
x+1 was defined as zero or negative:
> integrate(1/x, x, 0, 1);
> zero (or negative)
> give an error message.
The error message (stack overflow) in this case is clearly distinct from the
message indicating that the integral is divergent, which is what you get if
you specify x+1 as positive.
Anyhow, I note that our handling of inf (and minf, und, and infinity) leaves
a lot to be desired. For instance, 1/inf, inf-inf, 2*und, minf^2, 0*inf all
give questionable/incorrect results (see bug #820188). They can also be
reassigned (see bug #783847). Perhaps a revamping of the code handling these
symbols can go a long way towards resolving those concerns that presently
justify not evaluating the above definite integral to inf?
From: macrakis at gmail.com [mailto:macrakis at gmail.com] On Behalf Of Stavros
Sent: Monday, June 02, 2008 11:25 AM
To: Viktor T. Toth
Cc: ahmet alper parker; maxima at math.utexas.edu
Subject: Re: [Maxima] integrate(1/x,x,0,1)
On Mon, Jun 2, 2008 at 11:19 AM, Viktor T. Toth <vttoth at vttoth.com> wrote:
> There appear to be several problems (three at least) with Ahmet's example.
Yes, these are all bugs (and I think they have been reported before).
But they are orthogonal to the question of whether
integrate(1/x,x,0,1) should signal an error or not.
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