What is a Function? Definition, Types and Notation (2024)

What is a function? A function is defined as a relation between a set of inputs having one output each. In simple words, a function is a relationship between inputs where each input is related to exactly one output. Every function has a domain and codomain or range. A function is generally denoted by f(x) where x is the input. The general representation of a function is y = f(x).

These functions are also classified into various types, which we will discuss here. Check Relations and Functions lesson for more information.

What is a Function in Maths?

A function in maths is a special relationship among the inputs (i.e. the domain) and their outputs (known as the codomain) where each input has exactly one output, and the output can be traced back to its input.

Types of Functions in Maths

An example of a simple function is f(x) = x2. In this function, the function f(x) takes the value of “x” and then squares it. For instance, if x = 3, then f(3) = 9. A few more examples of functions are: f(x) = sin x, f(x) = x2 + 3, f(x) = 1/x, f(x) = 2x + 3, etc.

There are several types of functions in maths. Some important types are:

  • Injective function or One to one function: When there is mapping for a range for each domain between two sets.
  • Surjective functions or Onto function: When there is more than one element mapped from domain to range.
  • Polynomial function: The function which consists of polynomials.
  • Inverse Functions: The function which can invert another function.

These were a few examples of functions. It should be noted that there are various other functions like into function, algebraic functions, etc.

Learn here all the functions:

What is a Function in Algebra?

A function is an equation for which any x that can be put into the equation will produce exactly one output such as y out of the equation. It is represented as;

y = f(x)

Where x is an independent variable and y is a dependent variable.

For example:

  • y = 2x + 1
  • y = 3x – 2
  • y = 4y
  • y = 5/x

What is a function on a graph?

A function f(x) can be represented on a graph by knowing the values of x. As we know, y = f(x), so if start putting the values of x we can get the related value for y. Hence, we can plot a graph using x and y values in a coordinate plane. Let us see an example:

Suppose, y = x + 3

Then,

  • when x = 0, y = 3
  • when x = -2, y = -2 + 3 = 1
  • when x = -1, y = -1 + 3 = 2
  • when x = 1, y = 1 + 3 = 4
  • when x = 2, y = 2 + 3 = 5

Thus, with the help of these values, we can plot the graph for function x + 3.

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Frequently Asked Questions on Function

Q1

What is the definition of a function?

A function can be defined as a relation between a set of inputs where each input has exactly one output.

Q2

How are functions represented?

A function is generally represented as f(x).

Q3

What is the domain and codomain of a function?

A domain of a function is the set of inputs for which the function is defined. A codomain of a function is the set of possible output values.

What is a Function? Definition, Types and Notation (2024)

FAQs

What is a Function? Definition, Types and Notation? ›

A function is defined as a relation

relation
Relations Definition

A relation in mathematics defines the relationship between two different sets of information. If two sets are considered, the relation between them will be established if there is a connection between the elements of two or more non-empty sets.
https://byjus.com › maths › relations-and-its-types
between a set of inputs having one output each. In simple words, a function is a relationship between inputs where each input is related to exactly one output. Every function has a domain and codomain
codomain
In relations and functions, the codomain is the set of all possible outcomes of the given relation or function. Sometimes, the codomain is also equal to the range of the function. However, the range is the subset of the codomain.
https://byjus.com › maths › domain-codomain-range-functions
or range. A function is generally denoted by f(x) where x is the input.

What is function definition and types? ›

A function is defined as 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. Let A and B be two non-empty sets, mapping from A to B will be a function only when every element in set A has one end and only one image in set B.

What is the definition of a function and notation? ›

The notation f(x) defines a function named f. This is read as “y is a function of x.” The letter x represents the input value, or independent variable. The letter y is replaced by f(x) and represents the output value, or dependent variable.

What is function meaning type? ›

function, in mathematics, an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable (the dependent variable). Functions are ubiquitous in mathematics and are essential for formulating physical relationships in the sciences.

What is the mean of a function notation? ›

In calculus, and especially multivariable calculus, the mean of a function is loosely defined as the average value of the function over its domain. In one variable, the mean of a function f(x) over the interval (a,b) is defined by: Recall that a defining property of the average value of finitely many numbers.

How to identify a function? ›

To identify a function from a relation, check to see if any of the x values are repeated - if not, it is a function. If any x values are repeated, and the corresponding y values are different, then we have a relation and not a function.

What is an example of a function notation? ›

Function Notation. When a function is expressed as an equation, it is often written as "f(x)." In creating a table of values for an equation, for example y = 5x − 1, we use this rule, "multiply by five and subtract one" to transform an input x value into the one resulting y value.

What is an example of a notation? ›

A good example of notation is musical notation. This type of notation system contains many symbols and various types of graphics, and it allows a composer to inform others how he wants his or her music to sound and be performed.

Why is function notation used? ›

Function notation in maths is analogous to the list of ingredients you get given in a recipe. It won't tell you how to make the cake but it will tell you what ingredients you'll need to get when you go shopping! It's used practically in physics, and is one of the key elements in computer programming.

What is a function and example? ›

In particular, a function maps each input to exactly one output. A function can be expressed as an equation, a set of ordered pairs, as a table, or as a graph in the coordinate plane. One simple example of a function is multiplication by 3. As an equation, this would be written f(x) = 3x.

Which best defines a function definition? ›

A function is a special type of relation for which there is a rule that pairs each input with exactly one output. A function is a relationship that defines the connection between two variables.

What are the four main types of functions? ›

What are Types of Functions?
Based on ElementsOne-One Function Many-One Function Onto Function One-One and Onto Function Into Function Constant Function
Based on the EquationIdentity Function Linear Function Quadratic Function Cubic Function Polynomial Functions
2 more rows
May 4, 2023

What is a function notation for dummies? ›

The Basics of Function Notation

When you see f(x) f ( x ) , it means you're applying the function to the value . Essentially, you're saying, “Hey, the function , do your thing to . For example, if we have f(x)=2x f ( x ) = 2 x , it means that whatever number you put in for , the function will double it.

What are the three parts of the function notation? ›

A function has three parts, a set of inputs, a set of outputs, and a rule that relates the elements of the set of inputs to the elements of the set of outputs in such a way that each input is assigned exactly one output.

What does f mean in function notation? ›

A function is often denoted by a letter such as f, g or h. The value of a function f at an element x of its domain (that is the element of the codomain that is associated to x) is denoted by f(x); for example, the value of f at x = 4 is denoted by f(4).

What is function definition with example? ›

A function in algebra is an equation for which any x that can be put into the equation will produce exactly one output such as y out of the equation. It is represented as y = f(x), where x is an independent variable and y is a dependent variable. For example: y = 2x + 1. y = 3x – 2.

What are the 8 types of functions? ›

There are eight different types of functions that are commonly used, therefore eight different types of graphs of functions. These types of function graphs are linear, power, quadratic, polynomial, rational, exponential, logarithmic, and sinusoidal.

What is a function definition in C and types? ›

What are Functions in C? Functions are a fundamental building block of C programs and are used to modularize and organize code. They provide a way to break down a program into smaller, manageable units, which makes the code more readable, reusable, and maintainable. They are of two types: Built-in and User Defined.

What is the difference between function and function definition? ›

Function Declaration is used to let the compiler know about the existence of such a function so that we don't encounter any Reference Errors. Function Definition is used to provide the actual implementation of the code which will execute every time the function is called.

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