Finding horizontal asymptotes is very easy! Not all rational functions have horizontal asymptotes. the function must satisfy one of two conditions dependent upon the degree (highest exponent) of the numerator and denominator. If the degree of the numerator is equal to the degree of the denominator, then the horizontal asymptote is y= the ratio of the leading coefficients. If the degree of the denominator is greater than the degree of the numerator then y= 0. If the degree of the denominator is less than the degree of the numerator then the function does not have a horizontal asymptote. Several explanatory examples further clarify the principle.