Rational Functions

To create a rational function, just compute the quotient of two
polynomials.
Use the functions
numer and
denom to recover the numerator and
denominator of a fraction:
Since these are polynomials, you can apply all of the
polynomial operations to them.
You can substitute values or other rational functions for the variables
using the function eval. The syntax for
eval is similar to the one for polynomials: