Re: [Maxima-discuss] simplify_sum leads to a wrong value

[andre m. <and...@gm...>]

with gamma_expand to true I get for the original problem

-----
$ rmaxima
Maxima 5.45.1 https://maxima.sourceforge.io
using Lisp SBCL 2.0.1-8.fc36
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) display2d : false;

(%o1) false
(%i2) gamma_expand : true;

(%o2) true
(%i3) load("simplify_sum");

(%o3) "/usr/share/maxima/5.45.1/share/solve_rec/simplify_sum.mac"
(%i4) S : sum(sin(n*%pi/3)^3*cos(n*%pi/3)/n,n,1,inf);

(%o4) 'sum((cos((%pi*n)/3)*sin((%pi*n)/3)^3)/n,n,1,inf)
(%i5) h : ratsimp(simplify_sum(S));

(%o5) (3^(3/2)*%e+3^(3/2))/8
(%i6) h, numer;

(%o6) 2.415094891406689
-----

Don't miss your chances for discovering examples for Schanuel's conjecture ;-)

Regards Andre

On 5/17/23 16:09, Raymond Toy wrote:
>
> On 5/16/23 11:36, andre maute wrote:
>> FYI. simplify_sum gives for me a sum of 6 gamma_incomplete_lower terms
>>
>> with the help of
>> https://mathworld.wolfram.com/IncompleteGammaFunction.html
>> shouldn't e.g. gamma_incomplete_lower(4,-1) be computable exactly?
>
> It should be able to.
>
> Ah. you need to set gamma_expand to true.  Then the final result is 3^(3/2)*(1+%e)/8.  I think this is the correct value.  (Which is still the incorrect value for the original sum question.)
>
>
>
>
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