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Groups > comp.soft-sys.math.maple > #1193

Re: Simplifying exponential expressions

Cross-posted to 2 groups.

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On 30.08.2015 14:30, Peter Luschny wrote:
>> After simplify(), apply convert(%, exp).
>
> Thanks Rouben!
>
> The situation as I see it is: I want to go from San Francisco
> to Los Angles by car and buy a automotive navigation system.
> I start, follow the instructions and after a while I find
> myself in Las Vegas. So I call the manufacturer and complain.
> The manufacturer answers: Hey, there is another button on the
> device, the blue one, press it and it will lead you to Los
> Angeles. And indeed it does.
>
> So is this OK or absurd? I do know that an algorithmic solution
> of simplification problems require some regularizations and
> mapping to some standard internal representation before they
> can be solved. However it is the promise of a CAS to do this
> internally.
>
> In the examples I wanted expressions simplified to 1 or to 0
> not to an exponential expression. Other CASs understand this
> -- but not Maple.
>

I do not think that there is a generally agreed way. And you
example is not a good example, as many examples.

Maple thinks that cosh is more simple than exp, it does not
go that route without being directed. And it certainly does
not try all routes.

What I could 'accept' is: why  exp(x)+exp(-x) does not show
cosh when 'simplify' is called? But even that may have some
good reason: having more terms it may be that one does *not*
want that. For example consider some discounting function
and after 'simplify' one would end up in trigonometric terms.
Here it tries to simplify in terms of exp.

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Thread

Simplifying exponential expressions Peter Luschny <peter.luschny@gmail.com> - 2015-08-29 13:13 -0700
  Re: Simplifying exponential expressions rouben@shady-2.(none) (Rouben Rostamian) - 2015-08-30 04:37 +0000
    Re: Simplifying exponential expressions Peter Luschny <peter.luschny@gmail.com> - 2015-08-30 05:30 -0700
      Re: Simplifying exponential expressions Axel Vogt <&noreply@axelvogt.de> - 2015-08-30 15:24 +0200
        Re: Simplifying exponential expressions Peter Luschny <peter.luschny@gmail.com> - 2015-08-30 14:40 -0700
          Re: Simplifying exponential expressions Axel Vogt <&noreply@axelvogt.de> - 2015-08-31 22:10 +0200
  Re: Simplifying exponential expressions RGVickson@shaw.ca - 2015-09-15 10:50 -0700

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