Re: Integrate bug
- To: mathgroup at yoda.ncsa.uiuc.edu
- Subject: Re: Integrate bug
- From: dooley at goldengatesparc.Berkeley.EDU (Sam Dooley)
- Date: Mon, 25 Feb 91 09:53:53 PST
Mathematica's formulation of the anti-derivative involves
the Log function, and the direct substitution chose the
wrong branch. Applying the transformation Log[Exp[x]] -> x
happens to choose the right branch in this case, but this
will not always be true.
Mathematica (MIPS) 1.2 (November 8, 1989) [With pre-loaded data]
by S. Wolfram, D. Grayson, R. Maeder, H. Cejtin,
S. Omohundro, D. Ballman and J. Keiper
with I. Rivin and D. Withoff
Copyright 1988,1989 Wolfram Research Inc.
-- X11 windows graphics initialized --
In[1]:= Integrate[Exp[I x] Cos[x],x]
-I 2 I x -I I x
Out[1]= -- E + -- Log[E ]
4 2
In[2]:= % /. x -> 2 Pi
-I
Out[2]= --
4
----------
Sam Dooley
dooley at Berkeley.EDU