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Re: TeXForm and negative exponents


Hi,

Unprotect[Times]

Format[a_*E^(b_), TeXForm] := 
  SequenceForm[a, "\\,\\exp\\left({", b, "}\\right)"]

Protect[Times]

should do that.

Regards
  Jens

Jens Dreger wrote:
> 
> 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.


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