A function represents a mathematical relationship between two sets of real numbers. These sets of numbers are related to each other by a rule which assigns each value from one set to exactly one value in the other set. The standard notation for a function y = f(x), developed in the 18th century, is read "y equals f of x." Other representations of functions include graphs and tables. Functions are classified by the types of rules which govern their relationships including; algebraic, trigonometric, and logarithmic and exponential. It has been found by mathematicians and scientists alike that these elementary functions can represent many real-world phenomena.

History of functions

The idea of a function was developed in the 17th century. During this time, Rene Descartes (1596-1650), in his book Geometry (1637), used the concept to describe many mathematical relationships. The term "function" was introduced by Gottfried Wilhelm Leibniz (1646-1716) almost...