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Baffling change to partial derivative in version 5.1

• To: mathgroup at smc.vnet.net
• Subject: [mg61555] Baffling change to partial derivative in version 5.1
• From: Steven HANCOCK <Steven.Hancock at cern.ch>
• Date: Sat, 22 Oct 2005 00:35:59 -0400 (EDT)
• Organization: CERN
• Sender: owner-wri-mathgroup at wolfram.com

Please, can anyone explain (or even just reproduce) the following behaviour?


In[1]:=
$Version

Out[1]=
5.1 for Microsoft Windows (October 25, 2004)

In[2]:=
$ReleaseNumber

Out[2]=
0

In[3]:=
D[x y, t, NonConstants->{x}]

Out[3]=
y D[x, t, NonConstants -> {x}]

In[4]:=
D[x y, time, NonConstants->{x}]

Out[4]=
0


Merely changing the spelling of the variable from t to time does not 
return zero in version 4.2.
                             Thanks, Steve.

• Follow-Ups:
  • Re: Baffling change to partial derivative in version 5.1
    • From: Chris Chiasson <chris.chiasson@gmail.com>