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- To: mathgroup at smc.vnet.net
- Subject: [mg32239] TeXForm and negative exponents
- From: Jens Dreger <jens.dreger at physik.fu-berlin.de>
- Date: Wed, 9 Jan 2002 03:17:34 -0500 (EST)
- Organization: Freie Universitaet Berlin
- Sender: owner-wri-mathgroup at wolfram.com
Hi all!
I want to save some expressions in TeX-format like so:
  Put[TeXForm[expr],file]
where expr contains exponentials with negative exponents
which I want to show up in the output as _negative_.
For some reason, Mathematica always "simplifies" the
expression so it only contains positive exponents.
Example:
 In[1]:= TeXForm[1/(1 + 2 Exp[-3 t])]
 Out[1]:= \frac{1}{1 + \frac{2}{e^{3\,t}}}
Ok, so I thought, HoldForm might help:
 In[2]:= TeXForm[HoldForm[(1 + 2 Exp[-3 t] )]]
 Out[2]:= 1 + 2\,\exp (-3\,t)
Great, only my expression does not contain Exp[], but
the 2d form. In that case, HoldForm does not seem to do
the trick...
                                1
 In[3]:= TeXForm[HoldForm[--------------]
                          (1+2 e^{-3 t})
 Out[3]:= \frac{1}{1 + \frac{2}{e^{3\,t}}}
The output I want is:
 \frac{1}{1 + 2 e^{-3 t}}
Wrapping StandardForm around expr does seem to help,
but then the TeX-Output contains all kinds of special
commands, which I don't want. In this small example
it's ok, but not on the large expressions.
Is there an easy way, to get TeXFrom to do what I intend?
Thanks a lot in advance!
Jens.

