en.wikipedia.org/wiki/Function_(mathematics)

In mathematics, a function is a relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output.

www.mathsisfun.com/sets/function.html

But we are not going to look at specific functions ... ... instead we will look at the general idea of a function. Names. First, it is useful to give a function a name.

www.khanacademy.org/math/algebra/algebra-functions/evaluating-functions/v/what-is-a-function

In programming, the concept of functions came from the idea of functions in mathematics. How they are similar: In math: -You take some input values -You give ...

www.khanacademy.org/math/algebra/algebra-functions

Functions are mathematical entities that assign unique outputs to given inputs. Sounds simple? Think again! In this topic you will evaluate, graph, analyze, and ...

functions.wolfram.com

The world's largest collection of formulas and graphics about more than 300000 mathematical functions for the mathematics and science communities.

reference.wolfram.com/language/tutorial/SomeMathematicalFunctions.html.en

The Wolfram Language includes a very large collection of mathematical functions . "Mathematical Functions" gives the complete list. Here are a few of the ...

dlmf.nist.gov

Foreword · Preface · Mathematical Introduction · 1 Algebraic and Analytic Methods · 2 Asymptotic Approximations · 3 Numerical Methods · 4 Elementary ...

docs.microsoft.com/en-us/sql/t-sql/functions/mathematical-functions-transact-sql

Jul 6, 2017 ... Mathematical Functions (Transact-SQL) ... The following scalar functions perform a calculation, usually based on input values that are provided ...

www.britannica.com/topic/function-mathematics

function: in mathematics, an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable (the ...