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Re: ComplexExpand

• To: mathgroup at smc.vnet.net
• Subject: [mg5318] Re: [mg5302] ComplexExpand
• From: Sherman Reed <Sherman.Reed at worldnet.att.net>
• Date: Wed, 27 Nov 1996 01:47:35 -0500
• Sender: owner-wri-mathgroup at wolfram.com

At 06:44 AM 11/23/96 +0000, you 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

I get the same result when using 2.2.3 on Pent 166 w/32 mb ram.

however when I do the exercise on 3.0 on Pent 155 w/32 mb ram, I get

In[4]:=
ComplexExpand[Log[1/E^x]]
ComplexExpand[Log[1/(2*E^x)]]
Out[4]=
-x
Out[5]=
-x-Log[2]

which is what I would expect.  I cannot explain why, however.  I get the same
result on a NeXT using 2.2

Sherman Reed