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 :)
RJF
> -----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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