Horizontal Asymptotes: Horizontal asymptotes represent values toward which a graphed function approaches as x tends towards positive or negative infinity.
Rational Functions: Rational functions are ratios of two polynomial functions. They often have vertical asymptotes due to the restrictions on dividing by zero.
Limits at Infinity: Limits at infinity describe the behavior of a function as x approaches positive or negative infinity. These limits can help determine if a graph has vertical asymptotes.