Unfixed Bug in Mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg38661] Unfixed Bug in Mathematica
- From: smudge <smudge at shell01.TheWorld.com>
- Date: Fri, 3 Jan 2003 00:16:50 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
I reported this bug to Wolfram Research two years ago
when I found it in Mathematica version 4.0. I just got version 4.2
and the bug is still present, so I thought I'd report it
here again to give everyone a heads-up.
If I define
In[1]:= eq = D[f[x, y, t], x, t] + D[f[x, y, t], y, t];
and integrate it with respect to t I get
In[2]:= Integrate[eq, t]
(0,1,0)
Out[2]= 2 f [x,y,t]
which is clearly wrong. I also have an example where DSolve
shows the same erroneous behavior.
If I map the the integration over the expression I get the
correct result
In[3]:= Map[Integrate[#, t] &, eq]
(0,1,0) (1,0,0)
Out[3]= f [x,y,t] + f [x,y,t]
Russ Todd