en.wikipedia.org/wiki/Asymptote

In analytic geometry, an asymptote of a curve is a line such that the distance between the curve .... A common example of a vertical asymptote is the case of a rational function at a point x such that the denominator is zero and the numerator is ...

www.purplemath.com/modules/asymtote4.htm

Uses worked examples to demonstrate how to recognize and find vertical, horizontal, and slant asymptotes, along with the domain of a function.

www.mathsisfun.com/algebra/asymptote.html

Asymptote. An asymptote is a line that a curve approaches, as it heads towards infinity: Asymptote ... The curve can approach from any side (such as from above or below for a horizontal asymptote),. Asymptote ... y=x/2-1. Asymptote Example ...

www.softschools.com/math/calculus/finding_horizontal_asymptotes_of_rational_functions

Remember that an asymptote is a line that the graph of a function approaches but never touches. Rational functions contain asymptotes, as seen in this example ...

www.icoachmath.com/math_dictionary/asymptote.html

Asymptote is a line that a graph gets closer and closer to.....complete information about the asymptote, definition of an asymptote, examples of an asymptote, ...

www.onlinemathlearning.com/asymptote.html

Calculus: How to find Vertical Asymptote, Horizontal Asymptote and Oblique Asymptote, examples and step by step solutions, For rational functions, vertical ...

www.shmoop.com/precalc-polynomials/horizontal-examples.html

Examples · Rational Root Theorem · Restricting the Roots · Multiplicity · Sketching Polynomials · Vertical Asymptotes and Discontinuities; Horizontal and Slant ...

www.shmoop.com/functions-graphs-limits/vertical-asymptotes-holes-examples.html

Examples · One-Sided Limits · Finding Vertical Asymptotes; Vertical Asymptotes vs. Holes; Limits of Functions at Infinity · Finding Horizontal/ Slant/ Curvilinear ...

asymptote.sourceforge.net/links.html

Asymptote Tutorial by Charles Staats ... Asymptote modules and examples by Philippe Ivaldi · Another gallery of Asymptote examples by Gaétan Marris.