Can you have a slant and horizontal asymptote?
Thereof, can a function cross a slant asymptote?
NOTE: A common mistake that students make is to think that a graph cannot cross a slant or horizontal asymptote. This is not the case! A graph CAN cross slant and horizontal asymptotes (sometimes more than once). It's those vertical asymptote critters that a graph cannot cross.
- If n < m, the horizontal asymptote is y = 0.
- If n = m, the horizontal asymptote is y = a/b.
- If n > m, there is no horizontal asymptote.
Simply so, what is the equation of the horizontal or oblique asymptote?
Case 1: If the degree of the numerator of f(x) is less than the degree of the denominator, i.e. f(x) is a proper rational function, the x-axis (y = 0) will be the horizontal asymptote. The line y = mx + b is an oblique asymptote for the graph of f(x), if f(x) gets close to mx + b as x gets really large or really small.
A slant (oblique) asymptote occurs when the polynomial in the numerator is a higher degree than the polynomial in the denominator. To find the slant asymptote you must divide the numerator by the denominator using either long division or synthetic division.