On 2014-06-23, Karl Schultheisz <[email protected]> wrote:
> I'm using Sage 6.2 on Arch Linux. I have posted before about sums being
> wrong
><https://groups.google.com/d/msg/sage-support/IgC78rcdO7c/qTWzpA9f-P8J>,
> and I am happy to see that the community took action. Thanks! I have been
> seeing other errors that may or may not be related to those addressed in
> the link above.
>
> I open a new Sage session (command line). The following code ought to
> return (e^x - 1)/x.
>
> sage: k = var('k')
> sage: sum(x^k/factorial(k+1),k,0,oo)
> 1/4*sqrt(pi)*sqrt(x)*e^(1/2*x)
>
> This looks similar to the sort of nonsense it was spitting out when
> misinterpreting
> Bessel functions from Maxima <http://trac.sagemath.org/ticket/16224>. In
> the same session, if I run the summation command again, the result is
did you try applying the patch from #16224 ?
> different.
>
> sage: sum(x^k/factorial(k+1),k,0,oo)
> sum(x^k/factorial(k + 1), k, 0, +Infinity)
>
> And after this it will not simplify any sums, even ones it would have done
> correctly on the first try:
>
> sage: sum(x^k/factorial(k),k,0,oo)
> sum(x^k/factorial(k), k, 0, +Infinity)
>
> Even a reset doesn't help. (As a side-note, the exit command doesn't
> survive reset.)
>
> sage: reset()
> sage: k = var('k')
> sage: sum(x^k/factorial(k),k,0,oo)
> sum(x^k/factorial(k), k, 0, +Infinity)
> sage: exit
>
> ---------------------------------------------------------------------------
> NameError Traceback (most recent call
> last)
> /opt/sage/local/lib/python2.7/site-packages/sage/all_cmdline.py in
><module>()
> ----> 1 exit
>
> NameError: name 'exit' is not defined
>
> Finite sums seem to be ok.
>
> sage: sum(x^k,k,0,3)
> x^3 + x^2 + x + 1
> sage: m = var('m')
> sage: sum(x^k,k,0,m)
> (x^(m + 1) - 1)/(x - 1)
>
> Any help is greatly appreciated.
>
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