Maybe noninteractive.mac, abs_integrate.mac and pw.mac are all trying to fix the same thing? It seems there is an aversion to
expressing the answer in terms of abs(x) or even more so signum(x). Why is that, I don't know. These should not be considered
depreciated, undesirable functions.
Rich
----- Original Message -----
From: "Richard Hennessy" <rich.hennessy at verizon.net>
To: "Robert Dodier" <robert.dodier at gmail.com>
Cc: <maxima at math.utexas.edu>
Sent: Sunday, May 24, 2009 1:34 PM
Subject: Re: [Maxima] Seems like a bug in integrate
Someone pointed out correctly I think that the unqualified "best" answer to input 2 should be
(%i2) integrate(1/(x^2+1)*exp(-2*%i*%pi*x*t),x,minf,inf);
(%o2) %pi*%e^(- 2*%pi*abs(t))
This is a difficulty in Maxima since it was created without an ability to render output in piecewise fashion. Abs(t) is a piecewise
function that can be written pw([minf,-t,0,t,inf],x), maybe this is taking on too much but I wonder if noninteractive.mac could be
modified to output the unqualified correct answer using the pw function or in this case the abs function?
Rich
----- Original Message -----
From: "Robert Dodier" <robert.dodier at gmail.com>
To: "Richard Hennessy" <rich.hennessy at verizon.net>
Cc: "Dieter Kaiser" <drdieterkaiser at web.de>; <maxima at math.utexas.edu>
Sent: Sunday, May 24, 2009 1:21 AM
Subject: Re: [Maxima] Seems like a bug in integrate
On 5/22/09, Richard Hennessy <rich.hennessy at verizon.net> wrote:
> (%i1) integrate(1/(x^2+1)*exp(-%i*%pi*x*t),x,minf,inf);
> Is t positive, negative, or zero?
> p;
> (%o1) %pi*%e^(-%pi*t)
> (%i2) integrate(1/(x^2+1)*exp(-2*%i*%pi*x*t),x,minf,inf);
> Is t positive, negative, or zero?
> p;
> (%o2) %pi*%e^(- 2*%pi*t)
> (%i3) integrate(%*exp(2*%i*%pi*x*t),t,minf,inf);
> Maxima encountered a Lisp error:
> Unhandled kernel in tvar-lim
I see the same error with Maxima built from CVS.
Can you make a bug report about it? Thanks for your help.
Robert Dodier
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