Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1991
*January
*February
*March
*August
*September
*October
*November
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1991

[Date Index] [Thread Index] [Author Index]

Search the Archive

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


  • Prev by Date: psfix for Mathematica 2.0
  • Next by Date: Spirals and shells
  • Previous by thread: Integrate bug
  • Next by thread: RE: Integrate bug