plotting a parametric integral




On Fri, 9 Oct 2009, Richard Hennessy wrote:

< Of course as stated before if k is known then Maxima can do the problem.  It
< cannot do the general case for arbitrary k.
< 
< 
< Rich
< 
< ----- Original Message ----- From: "Richard Hennessy"
< <rich.hennessy at verizon.net>
< To: "Leo Butler" <l.butler at ed.ac.uk>; "Stanislav Maslovski"
< <stanislav.maslovski at gmail.com>
< Cc: <maxima at math.utexas.edu>
< Sent: Friday, October 09, 2009 9:04 PM
< Subject: Re: [Maxima] plotting a parametric integral
< 
< 
< > This integral cannot be done by Maxima.  Try
< > 
< > (%i4) display2d:false;
< > 
< > (%o4) false
< > (%i5) load(noninteractive);
< > 
< > (%o5)
< > "C:/Maxima-5.19.2/share/maxima/5.19.2/share/contrib/noninteractive/noninteractive.mac"
< > (%i6) integrate(exp(%i*k*x)*sin(x)/x,x,minf,inf);
< > 
< > (%o6) if k-1 < 0 then integrate(%e^(%i*k*x)*sin(x)/x,x,minf,inf) elseif
< > equal(k-1,0) then %pi else 0
< > 
< > The answer shows that when k-1<0 Maxima can't do the integration.
 
Rich,
This shows a weakness in the noninteractive code. If you walk through
the cases that 'integrate' throws up, you will see that it does
correctly identify all the various conditions on k. The noninteractive
result you show is not following the various cases that are thrown up.

Leo

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