Denominator after simplification : denom

denom (or getDenom) takes as argument a rational fraction and returns the denominator of an irreducible representant of this fraction (see also 1.8.4).
Input :

denom((x^2-1)/(x-1))

Output :

1

Input :

denom((x^2+2*x+1)/(x^2-1))

Output :

x-1