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