Example 1:
> denominator(5/3);
3
Example 2:
> denominator(exp(x));
1
Example 3:
> a = 5/3;
> b = numerator(a)/denominator(a);
> print(a);
5 / 3
> print(b);
5 / 3
Example 4:
> a = exp(x/3);
> b = numerator(a)/denominator(a);
> print(a);
exp(x / 3)
> print(b);
exp(x / 3)