Limit of a function

| Main Article
| Discussion
| Related Articles  [?]
| Bibliography  [?]
| External Links  [?]
| Citable Version  [?]

|
|
|
|
|
|
|
|

This editable Main Article is under development and subject to a disclaimer.

[edit intro]

The function (1+1n)n tends towards e as n tends towards infinity.

In mathematics, the concept of a limit is used to describe the behavior of a function as its argument either "gets close" to some point, or as it becomes arbitrarily large.

Suppose f(x) is a real-valued function and a is a real number. The expression

limx->af(x)=L

means that f(x) can be made arbitrarily close to L by making x sufficiently close to a. We say that "the limit of the function f of x, as x approaches a, is L". This does not necessarily mean that f(a) is equal to L, or that the function is even defined at the point a.

Limit of a function can in some cases be defined even at values of the argument at which the function itself is not defined. For example,

limx->0sin⁡(x)x=1,

although the function

f(x)=sin⁡(x)x

is not defined at x=0.

### Formal definition[edit]

Let f be a function defined on an open interval containing a (except possibly at a) and let L be a real number.

limx->af(x)=L

means that

for each real ε > 0 there exists a real δ > 0 such that for all x with 0 < |x − a| < δ, we have |f(x) − L| < ε.

This formal definition of function limit is due to the German mathematician Karl Weierstrass.

## See also[edit]

* Limit (mathematics)
* Limit of a sequence