FourierTransform
- To: mathgroup at smc.vnet.net
- Subject: [mg34336] FourierTransform
- From: Michael Hartl <susiarglos at gmx.de>
- Date: Wed, 15 May 2002 03:35:34 -0400 (EDT)
- Reply-to: Mike Hartl <susiarglos at gmx.de>
- Sender: owner-wri-mathgroup at wolfram.com
Some time ago I encountered following curious results from
FourierTransform in V 4.1.0 for the Fourier transform of 4 equivalent
expressions and notified WRI's support. In[3] and In[4] give correct
results while the equivalent expressions In[5] and In[6] differ. Is
there anything wrong with the syntax? Especially the dependency on the
variable name (u in In[5] and b in In[6]) puzzles me. (Results in V
4.0.1 were different but not consistent too.)
In[1]:= $Version
Out[1]= 4.1 for Microsoft Windows (November 2, 2000)
In[2]:= $ReleaseNumber
Out[2]= 0
In[3]:= FourierTransform[Exp[I a + I x u], x, k]
I a
Out[3]= E Sqrt[2 Pi] DiracDelta[k + u]
In[4]:= FourierTransform[Exp[I a + I x b], x, k]
I a
Out[4]= E Sqrt[2 Pi] DiracDelta[b + k]
In[5]:= FourierTransform[Exp[I (a + x u)], x, k]
Out[5]= 0
In[6]:= FourierTransform[Exp[I (a + x b)], x, k]
I (a + b x)
Out[6]= FourierTransform[E , x, k]
Mike