I have a very big rational function and i want to obtain the numerator and denominator. with .numerator_denominator() it takes forever with .numerator_denominator(False) not every term is expanded. with .expand() and .combine() it takes forever and the result is not a single fraction.
I need a single fraction N(x)/D(x) where N and D are polynomials in x, it is not important how big !
