Asymptote

When a straight line approaches a curve; such that, even if said curve were extended infinitely, the line would never meet it; then, the line and curve are asymptotes of each other. A "real-life" example of such an asymptotic relationship would involve a kitten standing 1m from a box[?]; and, if every second the kitten walks halfway to the box; this results in a situation in which the kitten never reaches the box; because, the distance it travels, during each second, is never more than halfway to to the box.

A specific example of asymptotes can be found in the graph of the function f(x) = 1 / x, in which two asymptotes are being approached: the line y = 0 and the line x = 0. The curve approaches them, but, never reaches them. A curve approaching a vertical asymptote (such as in the preceding example's y = 0, which has an undefined slope) could be said to approach an "infinite limit", although infinity is not technically considered a limit. A curve approaching a horizontal asymptote (such as in the preceding example's x = 0, which has a slope of 0) does approach a "true limit".

Asymptotes do not need to be parallel to the x- and y-axes, as shown by the graph of x + x^-1, which is asymptotic to both the y-axis and the line y = x.

A function f(x) can be said to be asymptotic to a function g(x) as x->∞. This has any of four distinct meanings:

1. f(x) - g(x) -> 0.
2. f(x) / g(x) -> 1.
3. f(x) / g(x) has a nonzero limit.
4. f(x) / g(x) is bounded and does not approach zero. See Big O notation.