[N,D] = numden(A)
simplifyFraction(expr)
simplifyFraction(expr,'Expand',true)
%%%%
% simplifyFraction(expr) simplifies the rational expression expr such that the
% numerator and denominator have no divisors in common.
%
% simplifyFraction(expr,'Expand',true) expands the numerator and denominator
% of the resulting simplified fraction as polynomials without factorization.