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Re: Output display of exponential function in Mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg62710] Re: Output display of exponential function in Mathematica
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Fri, 2 Dec 2005 05:53:08 -0500 (EST)
• Organization: The Open University, Milton Keynes, UK
• References: <dmbqgl$q9h$1@smc.vnet.net> <dmlvu8$mbp$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

New Guy wrote:
> I'm trying to just check and see if I got a whole bunch of
> even-numbered study exercises right on exponents and natural logs.
> The answers to the odds are in the book.
> 
> As an example, LN(1/e^2) equals what?
> 
> My answer is -1/2.
> 
> In mathematica, I tried Simplify[LN(1/e^2)] and it just spit the same
> thing out as the output.  I also tried a couple of variations of
> Solve[LN[1/e^2] = X] with essentially the same result
> 
> How would you get Mathematica to verify that the answer is -1/2.

Use the correct syntax :-) The natural logarithm of the number a, say, 
is written Log[a]. Check

http://documents.wolfram.com/mathematica/functions/Log

Now, the base of the natural logarithm is written E (capital e). 
Therefore, you can check your answer with

In[1]:=
Log[1/E^2]

Out[1]=
-2

(Hint: Log[1/E^2] <==> Log[1] - Log[E^2]...)

Hope this helps,
/J.M.