Mathematical limits are used to describe the behaviour of a function as it gets close to a point where the function is not necessarily defined.
Limits are very important in calculus .
They are also closely related to the idea of continuity . Assume we have a function f which might not be properly defined at a point p . If the ordinary limit is defined, both the limit from above and the limit from below are also defined, and all three agree. For arbitrary functions and points, there is no guarantee that a limit exists. The limit as x approaches 3 of x 2 is 9.