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.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.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.

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

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

functions.wolfram.com/alphabeticalIndex.html

Search Site. **Function** Categories · Graphics Gallery · Notations · General
Identities About This Site · Contribute · Email Comments · Elementary **Functions**.

reference.wolfram.com/language/guide/MathematicalFunctions.html

The Wolfram Language has the most extensive collection of **mathematical**
**functions** ever assembled. Often relying on original results and algorithms
developed ...

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 ...

www.thefreedictionary.com/mathematical+function

Noun, 1. **mathematical function** - (mathematics) a mathematical relation such that
each element of a given set (the domain of the function) is associated with an ...