Re: Some bugs in Mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg59450] Re: Some bugs in Mathematica
- From: "Dana DeLouis" <delouis at bellsouth.net>
- Date: Wed, 10 Aug 2005 02:56:03 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
> ... I made two misprints when typing formula.
> Instead of Gamma[n-k-1], it should be \Pi Gamma[n-k]. I apologize for
> the confusion.
Hi. For your first example, I see that the equation is now:
equ[n_]:=Sum[(Gamma[-k+n-1/2]*Gamma[k+1/2])/
(Pi*Gamma[n-k]*Gamma[k+1]),
{k,0,n-1}]
It looks to me that one gets an answer of 1 only if n is a positive integer.
Examples:
equ[4]
1
equ[7]
1
However, if n is not a positive integer, then the answer is not 1.
equ[8.3]
0.9112451645862876
It appears that you have to tell Mathematica to make the assumptions that n
is an integer. However, the following below was returned unevaluated. I
tried all variations on the theme below, but could not get a return value of
1. Maybe someone can jump in and take it from here...
Assuming[n>=1&&Element[n,Integers],
Sum[(Gamma[-k+n-1/2]*Gamma[k+1/2])/
(Pi*Gamma[n-k]*Gamma[k+1]),
{k,0,n-1}]]
<returned unevaluated...>