**Horizontal Asymptotes**

The graph of a rational function has at most one horizontal asymptote.

The graph of a rational function has a horizontal asymptote at y=0 if the degree of the denominator is greater than the degree of the numerator.

If the degrees of the numerator and the denominator are equal, then the graph has a horizontal asymptote at y=a/b, where a is the coefficient of the term of highest degree in the numerator and b is the coefficient of the term of the highest degree in the denominator.

If the degree of the numerator is greater than the degree of the denominator, then the graph has no horizontal asymptote.

The graph of a rational function has a horizontal asymptote at y=0 if the degree of the denominator is greater than the degree of the numerator.

If the degrees of the numerator and the denominator are equal, then the graph has a horizontal asymptote at y=a/b, where a is the coefficient of the term of highest degree in the numerator and b is the coefficient of the term of the highest degree in the denominator.

If the degree of the numerator is greater than the degree of the denominator, then the graph has no horizontal asymptote.