MathGroup Archive 1997

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Re: Re: trig expansion

  • To: mathgroup at smc.vnet.net
  • Subject: [mg9347] Re: [mg9323] Re: trig expansion
  • From: seanross at worldnet.att.net
  • Date: Sat, 1 Nov 1997 03:33:34 -0500
  • Sender: owner-wri-mathgroup at wolfram.com

Paul Abbott wrote:
> 
> Murray Eisenberg wrote:
> 
> > I find that really unpleasant to have to do!  I expect to be able to
> > tell Mathematica that T = k/omega and that k is an integer and have
> > *Mathematica* figure out what the Sin and Cos reduce to.
> >
> > It's all a question of expectation vs. reality of the language design,
> > of course.  Is my expectation unreasonable?
> 
> Let me ask another (related) question.  If you enter
> 
>         BesselJ[n+1/2,x]
> 
> for k an integer what do you expect Mathematica to return?  My point is
> that closed-form formulas exist as a consequence of n being an integer.
> How far through the system do you expect this functionality to extend?
> 
> Cheers,
>         Paul
> 
> ____________________________________________________________________
> Paul Abbott                                   Phone: +61-8-9380-2734
> Department of Physics                           Fax: +61-8-9380-1014
> The University of Western Australia            Nedlands WA  6907
> mailto:paul at physics.uwa.edu.au  AUSTRALIA
> http://www.pd.uwa.edu.au/~paul
> 
>             God IS a weakly left-handed dice player
> ____________________________________________________________________

The message wasn't addressed to me, but I will respond.  I want a
language with object-oriented type declarations where I can declare a
certain symbol to be integer, real, imaginary, rank 2 tensor etc. and
have every symbolic function in the system recognize and process
accordingly.  I want numeric functions that do not return ridiculous,
five-screen-long symbolic expressions when I make a mistake on symbols
I declare to be numerical quantities, instead returning an error
message informing me that no value has been entered for such and such a
numeric quantity.  I also want the system to behave just like
mathematica does now if I do not declare a symbol specifically to be of
a certain type.


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