On 5/9/07, Timothy Clemans <[EMAIL PROTECTED]> wrote:
>
> Oh. How do I check if something is an integer, rational, real, or complex?
>
In general, in mathematics, it can be very hard to determine whether
or not a number is real, etc. -- many subtle problems can be phrased
in terms of asking whether or not a number is rational, etc. Do you
know how to prove that pi is irrational? transcendental? However in
SAGE in most cases you can use "in", e.g.,
sage: 3 in ZZ
True
sage: 3/1 in ZZ
True
sage: 2/3 in ZZ
False
sage: sqrt(2) in QQ
False
> On 5/9/07, William Stein <[EMAIL PROTECTED]> wrote:
> > is_RealNumber checks that the data type of the input is a RealNumber,
> > i.e., has parent a real field. It does not check whether the object
> > itself has some sort of abstract mathematical meaning as a real
> > number.
> >
> > On 5/9/07, Timothy Clemans <[EMAIL PROTECTED]> wrote:
> > > {{{
> > > is_RealNumber(3)
> > > ///
> > > False
> > > }}}
> > >
> > > {{{
> > > is_RealNumber(sqrt(2))
> > > ///
> > > False
> > > }}}
> > >
> > > {{{
> > > is_RealNumber(pi)
> > > ///
> > > False
> > > }}}
> > >
> >
> >
> > --
> > William Stein
> > Associate Professor of Mathematics
> > University of Washington
> > http://www.williamstein.org
> >
>
> >
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://www.williamstein.org
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