# Re: "frac2" button

```then how do you explain how the ti-92 does it?  I want some kind of
symbolic manipulation, that i hear ppl are working on!!!

RWW Taylor <RWTNTS@RITVAX.ISC.RIT.EDU> wrote in article
<01ISU8F74CAUCIRDY1@ritvax.isc.rit.edu>...
>           "IT'S ALL IN THE DOTS"
>
> > I was wondering if there was any program out there that can
> > convert a decimal into a true fraction. like say .866025...
> > is really the squareroot of 3 over 2. or 1.04719... is really
> > pi over 3. i was looking for a "frac2" button.
>
> The decimal 0.866 is not exactly equal to half of the square root of 3,
> and it is not reasonable to expect the calculator to tell you that it is.
>
> The decimal 0.866025 is not exactly equal to half of the square root of
3,
> and it is not reasonable to expect the calculator to tell you that it is.
>
> The decimal ....    wait a minute!
>
> As soon as you can input a decimal that is _exactly_ equal to half the
square
> root of 3, then you can start thinking about how to create a "frac2"
button
> that will report this.  But that will be a very long time!
>
> The best you can possibly do is make a _guess_ or a _bet_ that the
decimal
> value in your hands was really meant to be an approximation of some
particular
> easily-described irrational value.  If you have some 12- or 13-place
> representation stored in memory W, for example, you might try using >Frac
on
> W^2 and decide whether you like what you see.  Another plausible effort
might
> be to divide W by pi (and try >Frac again, maybe).  Of course, what you
have
> might just be a representation of 2 minus the square root of 3, or the
cube
> root of 5 plus the cube root of 7, or pi^2, or some weirder number that
you
> will never guess the secret of.  Calculators are wonderful, but they have
no
> supernatural powers of divination (as far as I know, anyway).  :-)}
>
> RWW Taylor
> National Technical Institute for the Deaf
> Rochester Institute of Technology
> Rochester NY 14623
>
> >>>> The plural of mongoose begins with p. <<<<
>

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