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Topic: Re: [mg5302] ComplexExpand
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Daniel Lichtblau

Posts: 1,756
Registered: 12/7/04
Re: [mg5302] ComplexExpand
Posted: Nov 26, 1996 3:40 AM
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E. Neely Atkinson wrote:
>
> Can anyone explain to me why the following two
> examples behave differently? Thanks.
>
> Mathematica 2.2 for IBM RISC System/6000
> Copyright 1988-93 Wolfram Research, Inc.
> -- Terminal graphics initialized --
>
> In[1]:= ComplexExpand[Log[1 / E^x]]
>
> Out[1]= -x
>
> In[2]:= ComplexExpand[Log[1 / (2 E^x)]]
>
> 1
> Out[2]= Log[----]
> x
> 2 E
>
>
>
> E. Neely Atkinson
> neely@biomath.mdacc.tmc.edu


Looks like a minor bug. The result is tolerable because it is separated
into explicitly real and imaginary parts. The latter just happens to be
zero, because x is assumed real.

Works better in version 3.0.

In[2]:= ComplexExpand[Log[1 / (2 E^x)]]
Out[2]= -x - Log[2]

In[3]:= $Version
Out[3]= Linux 3.0 (October 4, 1996)

Daniel Lichtblau
Wolfram Research
danl@wolfram.com







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