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[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? > 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