Re: Problem with derivate of product
- To: mathgroup at smc.vnet.net
- Subject: [mg67338] Re: [mg67309] Problem with derivate of product
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Sun, 18 Jun 2006 05:13:50 -0400 (EDT)
- References: <200606170836.EAA28052@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On 17 Jun 2006, at 17:36, Esa A E Peuha wrote:
> Mathematica 5.0 seems to have trouble with parsing this input:
>
> In[1]:= D[Product[f[k,z],{k,0,m}],{z,n}]
>
> Out[1]= D[Product[f[k, z], {k, 0, m}], z]
>
> Has this been fixed in newer versions?
>
> --
> Esa Peuha
> student of mathematics at the University of Helsinki
> http://www.helsinki.fi/~peuha/
>
No. Also, I do not think there is any plan to "fix it" because it is
not considered to be "broken". Mathematica does not transform in any
way products or sums with symbolic limits unless it can evaluate them
in "closed form" (which obviously it can't in the case of an unknown
function f). The reason why it does not do so is , I think, due to
the following "basic principle of computer algebra systems": never
implement anything which cannot be done better "by hand", or if it is
only going to be useful in a few very special situations.
Andrzej Kozlowski
- References:
- Problem with derivate of product
- From: Esa A E Peuha <esa.peuha@helsinki.fi>
- Problem with derivate of product