On 11/2/07, Richard Fateman <fateman at cs.berkeley.edu> wrote:
> Mathematica 6.0 gives +infinity for both directions, as well as undirected.
> It has been suggested here, recently, that the limit calculations should be
> reprogrammed along the lines of a recent PhD dissertation by Dominik Gruntz.
>
> I think your example answers your own question about whether you can really
> trust the current program :)
:-)
Thanks, Richard. Apparently, Mathematica is also wrong: plot the graph
of the function. Maple 11 gives +oo for the first limit and -oo for
the second one, which is consistent with the graph of the function.
Paul
> > -----Original Message-----
> > From: maxima-bounces at math.utexas.edu
> > [mailto:maxima-bounces at math.utexas.edu] On Behalf Of Paul Smith
> > Sent: Friday, November 02, 2007 8:33 AM
> > To: maxima at math.utexas.edu
> > Subject: Wrong limits
> >
> > Dear All,
> >
> > Take the code:
> >
> > (%i1)
> > h:-(k^(k/(k-1))*(2*k-1)*2^(k/(k-1)))/((k-1)*(k*2^((2*k)/(k-1))
> -2^((2*k)/(k-1))-2*k+1))$
> >
> > (%i2) limit(h,k,1/3,plus);
> > log(3)
> > ------
> > 2
> > 3 %e
> > (%o2) -----------
> > 160 sqrt(2)
> > (%i3) limit(h,k,1/3,minus);
> > log(3)
> > ------
> > 2
> > 3 %e
> > (%o3) -----------
> > 160 sqrt(2)
> > (%i4)
> >
> > Both limits are wrong: the first one is +oo and the second one is -oo.
> > Can one really trust Maxima regarding the calculation of limits?
> >
> > Thanks in advance,
> >
> > Paul
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> >
>
>