Andrej Vodopivec said: (by the date of Thu, 11 Mar 2010 09:15:32 +0100)
> > An aside: ?I thought that nusum(1/n^2,n,1,inf) knew that the answer is
> > %pi^2/6, but it doesn't now. ?Perhaps my memory is wrong.
>
> nusum in general does not work well for infinite sums. simpsum knows
> how to do it.
>
> (%i1) sum(1/n^2,n,1,inf)$
> (%i2) %, simpsum;
> (%o2) %pi^2/6
wow, indeed, reversing sum & integral works! Just the same as I did
when doing with pen&paper myself ;)
sum(integrate(1/(n^4+x^2),x,0,inf), n, 1, inf),simpsum;
thanks a lot! :)
--
Janek Kozicki http://janek.kozicki.pl/ |