       Re: Problem with derivate of product

• To: mathgroup at smc.vnet.net
• Subject: [mg67322] Re: Problem with derivate of product
• From: Peter Pein <petsie at dordos.net>
• Date: Sun, 18 Jun 2006 05:13:15 -0400 (EDT)
• References: <e70fid\$rmp\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Esa A E Peuha schrieb:
> Mathematica 5.0 seems to have trouble with parsing this input:
>
> In:= D[Product[f[k,z],{k,0,m}],{z,n}]
>
> Out= D[Product[f[k, z], {k, 0, m}], z]
>
> Has this been fixed in newer versions?
>
Hi Esa,

I don't know what's going on there, but

pfn = Derivative[n][Product[f[k, #1], {k, 0, m}] & ][z]
Derivative[n][Product[f[k, #1], {k, 0, m}] & ][z]

seems to be a workaround:

Expand[pfn /. {f -> (1 + #2/(1 + #1) & ), m -> 5, n -> 2}]
203/45 + (49*z)/8 + (35*z^2)/12 + (7*z^3)/12 + z^4/24

Expand[D[Times @@ (1 + z/(1 + #1) & ) /@ Range[0, 5], {z, 2}]]
203/45 + (49*z)/8 + (35*z^2)/12 + (7*z^3)/12 + z^4/24

Peter

```

• Prev by Date: Re: Mathematica bugs?
• Next by Date: Re: Problem with derivate of product
• Previous by thread: Re: Problem with derivate of product
• Next by thread: Re: Problem with derivate of product