See Example. b m xm y a a n xn n x n b m x m, Tags used to find all horizontal asymptotesThe degree of the numerator is greater than the degree of. the denominator. Graph rational functions. the denominator. The vertical asymptotes of a rational function will occur where the denominator of the function is equal to zero and the numerator is not zero. Suppose we know that the cost of making a product is dependent on the number of items, x, produced. There is no horizontal asymptoteTaking the limit