7.7.4.0. isRational

Usage:

isRational(n); n number

Return:

int

Purpose:

determine whether n is a rational number,
that is it does not contain parameters.

Assume:

ground field is of characteristic 0

LIB "dmod.lib";
ring r = (0,a),(x,y),dp;
number n1 = 11/73;
isRational(n1);
==> 1
number n2 = (11*a+3)/72;
isRational(n2);
==> 0