Re: Inconsistent behavior?
- To: mathgroup at smc.vnet.net
- Subject: [mg87287] Re: Inconsistent behavior?
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Sun, 6 Apr 2008 06:45:40 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <ft7ggo$bs3$1@smc.vnet.net>
angela wrote:
> Binomial[n,4] yields
> 1/24 (-3+n) (-2+n) (-1+n) n
>
> Binomial[n,5] yields
> 1/120 (-4+n) (-3+n) (-2+n) (-1+n) n
>
> Binomial[n,6] yields
> Binomial[n,6]
>
> Binomial[n,7] yields
> Binomial[n,7]
>
> Is some setting doing this.
You can use *FunctionExpand* to get the expanded form. For instance,
In[1]:= Binomial[n, 6] // FunctionExpand
Out[1]=
1
--- (-5 + n) (-4 + n) (-3 + n) (-2 + n) (-1 + n) n
720
In[2]:= Binomial[n, 7] // FunctionExpand
Out[2]=
(-6 + n) (-5 + n) (-4 + n) (-3 + n) (-2 + n) (-1 + n) n
-------------------------------------------------------
5040
Regards,
-- Jean-Marc