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
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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