On Tue, Apr 24, 2012 at 5:16 PM, Tom Bachmann <e_mc...@web.de> wrote: >> I agree. Can you open an issue for this in our issue tracker >> (http://code.google.com/p/sympy/issues/list)? >> >> We can do hypergeometric series, which is why the summation() function >> is so powerful in the git master, but I think it's not recognizing >> this one as such because it's a finite sum (Tom, please correct me if >> I'm wrong). If you use the fact that binomial(n, k) == 0 for k> n, >> and replace n with oo in the summation limits, you get: >> > > I was about to say precisely that.
So any thoughts on how to fix it. I guess we should try to recognize if the summand is zero for all but finitely many values. And then do some manipulation on the indices. By the way, I just noticed: In [156]: summation( binomial(n,k), (k,n - 1, oo)) Out[156]: ⅈ⋅π n - ℯ That exp_polar() should probably be evaluated in the result. Aaron Meurer -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.