Answer:
Not true.
Explanation:
A rational function is like P(x) / Q(x) where P and Q are polynomials.
Examples would be x^2 / (x^2 - 2) and x^2 / (x^2 + 2).
Now the first one will have a vertical asymptote at x = √2 because this value would make the denominator zero.
The second one will have no asymptotes because the only value that would make x^2 + 2 = zero is not real (it would be √2i). So the domain of this is all real numbers , and no asymptotes.