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MathGroup Archive 1997

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Re: How to make Mathematica to return "Log[Exp[x]]" as x?

  • To: mathgroup at
  • Subject: [mg5785] Re: How to make Mathematica to return "Log[Exp[x]]" as x?
  • From: David Pearson <sgspedav at>
  • Date: Sat, 18 Jan 1997 14:58:37 -0500
  • Organization: University of Reading, U.K.
  • Sender: owner-wri-mathgroup at

On 7 Jan 1997, Cheng Li wrote:

> Dear friends, suppose x is a variable and when I type "Log[Exp[x]]" and then 
> enter, Mathematica gives me "Log[Exp[x]]" back. Could you please tell me how 
> to let Mathematica to return "Log[Exp[x]]" as x?


Try ComplexExpand[ Log[Exp[x]] ].

The reason it doesn't default to x is that Log is a
many-valued function in complex analysis.


 David Pearson,            Phone: (0)1743 318741    
 ESSC, PO Box 227,         Fax:   (0)1734 755865
 University of Reading,    email: sgspedav at           
 Reading, RG6 6AB, UK.     internet:         

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