The types of functions are defined on the basis of the domain, range, and function expression. The expression used to write the function is the prime defining factor for a function. Along with expression, the relationship between the elements of the domain set and the range set also accounts for the type of function. The classification of functions helps to easily understand and learn the different types of functions.
Every mathematical expression which has an input value and a resulting answer can be conveniently presented as a function. Here we shall learn about the types of functions and their definition, examples.
1.  What are the Types of Functions? 
2.  Representation of Functions 
3.  List of Types of Functions 
4.  Types of Functions  Based on Set Elements 
5.  Types of Functions  Based on Equation 
6.  Types of Functions  Based on Range 
7.  Types of Functions  Based on Domain 
8.  FAQs on Types of Functions 
What are the Different Types of Functions?
The function y = f(x) is classified into different types of functions, based on factors such as the domain and range of a function, and the function expression. The functions have a domain x value that is referred as input. The domain value can be a number, angle, decimal, fraction. Similarly, the y value or the f(x) value (is generally a numeric value) is the range. The types of functions have been classified into the following four types.
 Based on the Set Elements
 Based on Equation
 Based on Range
 Based on Domain
Representation of Functions
There are three different forms of representation of functions. The functions need to be represented to showcase the domain values and the range values and the relationship between them. The functions can be represented with the help of Venn diagrams, graphical formats, and roster forms. The details of each of the forms of representation are as follows.
Venn Diagram: The Venn diagram is an important format for representing the function. The Venn diagrams are usually presented as two circles with arrows connecting the element in each of the circles. The domain is presented in one circle and the range values are presented in another circle. And the function defines the arrows, and how the arrows connect the different elements in the two circles.
Graphical Form: Functions are easy to understand if they are represented in the graphical form with the help of the coordinate axes. Representing the function in graphical form, helps us to understand the changing behavior of the functions if the function is increasing or decreasing. The domain of the function  the x value is represented along the xaxis, and the range or the f(x) value of the function is plotted with respect to the yaxis.
Roster Form: Roster notation of a set is a simple mathematical representation of the set in mathematical form. The domain and range of the function are represented in flower brackets with the first element of a pair representing the domain and the second element representing the range. Let us try to understand this with the help of a simple example. For a function of the form f(x) = x^{2}, the function is represented as {(1, 1), (2, 4), (3, 9), (4, 16)}. Here the first element is the domain or the x value and the second element is the range or the f(x) value of the function.
List of Types of Functions
The types of functions are classified further to help for easy understanding and learning. The types of functions have been further classified into four different types, and are presented as follows.
Based on Elements 

Based on Equation 

Based on the Range 

Based on the Domain 

Types of Functions  Based on Set Elements
These types of functions are classified based on the number of relationships between the elements in the domain and the codomain. The different types of functions based on set elements are as follows.
One One Function
A onetoone function is defined by f: A → B such that every element of set A is connected to a distinct element in set B. The onetoone function is also called an injective function. Here every element of the domain has a distinct image or codomain element for the given function.
Many to One Function
A many to one function is defined by the function f: A → B, such that more than one element of the set A are connected to the same element in the set B. In a many to one function, more than one element has the same codomain or image. If a many to one function, in the codomain, is a single value or the domain element are all connected to a single element, then it is called a constant function.
Onto Function
In an, onto function, every codomain element is related to the domain element. For a function defined by f: A → B, such that every element in set B has a preimage in set A. The onto function is also called a subjective function.
One One and Onto Function (Bijection)
A function that is both a one and onto function is called a bijective function. Here every element of the domain is connected to a distinct element in the codomain and every element of the codomain has a preimage. Also in other words every element of set A is connected to a distinct element in set B, and there is not a single element in set B which has been left out.
Into Function
Intofunction is exactly opposite in properties to an onto function. Here there are certain elements in the codomain that do not have any preimage. The elements in set B are excess and are not connected to any elements in set A.
Constant Function
A constant function is an important form of a many to one function. In a constant function, all the domain elements have a single image. The constant function is of the form f(x) = K, where K is a real number. For the different values of the domain(x value), the same range value of K is obtained for a constant function.
Types of Function  Based on Equation
The algebraic expressions are also functions and are based on the degree of the polynomial. The functions based on equations are classified into the following equations based on the degree of the variable 'x'.
 The polynomial function of degree zero is called a Constant Function.
 The polynomial function of degree one is called a Linear Function.
 The polynomial function of degree two is called a Quadratic Function.
 The polynomial function of degree three is a Cubic Function.
Let us understand each of these functions in detail.
Identity Function
The identity function has the same domain and range. The identity function equation is f(x) = x, or y = x. The domain and range of the identity function is of the form {(1, 1), (2, 2), (3, 3), (4, 4).....(n, n)}.
The graph of the identity function is a straight line that is equally inclined to the coordinate axes and is passing through the origin. The identity function can take both positive and negative values and hence it is present in the first and the third quadrants of the coordinate axis.
Linear Function
A polynomial function having the firstdegree equation is a linear function. Thedomain and range of a linear function is a real number, and it has a straight line graph. Equations such as y = x + 2, y = 3x, y = 2x  1, are all examples of linear functions. The identity function of y = x can also be considered a linear function.
The general form of a linear function is f(x) = ax + b, is used to represent objective functions in linear programming problems.Here x, y are variables, anda, b are real numbers. Graphicallythe linear function can be represented by the equation of a line y = mx + c, where m is the slope of the line and c is the yintercept of the line.
Quadratic Function
A quadratic function has a seconddegree quadratic equation and it has a graph in the form of a curve. The general form ofthe quadratic function is f(x) = ax^{2} + bx + c, where a ≠ 0 and a, b, c are constant andx is a variable. The domain and range of the quadratic function is R.
The graph of a quadratic equation is a nonlinear graph and is parabolic in shape. Examples of quadratic functions are f(x) = 3x^{2} + 5, f(x) = x^{2}  3x + 2.
Cubic Function
A cubic function has an equation of degree three. The general form of a cubic function is f(x) = ax^{3} + bx^{2} + cx +d, where a ≠ 0 and a, b, c, and d are real numbers & x is a variable. The domain and range of a cubic function is R.
The graph of a cubic function is more curved than the quadratic function. An example of cubic function is f(x) = 8x^{3} + 5x^{2} + 3.
Polynomial Function
The general form of a polynomial function is f(x) = a^{n}x^{n} + a^{n1}x^{n1} + a^{n2}x^{n2}+ ..... ax + b. Here n is a nonnegative integer and x is a variable. The domain and range of a polynomial function are R. Based on the power of the polynomial function, the functions can be classified as a quadratic function, cubic function, etc.
Types of Functions  Based on Range
Here the types of functions have been classified based on the range which is obtained from the given functions. The different types of functions based on the range are as follows.
Modulus Function
The modulus function gives the absolute value of the function, irrespective of the sign of the input domain value. The modulus function is represented as f(x) = x. The input value of 'x' can be a positive or a negative expression. The graph of a modulus function lies in the first and the second quadrants since the coordinates of the points on the graph are of the form (x, y), (x, y).
Rational Function
A function that is composed of two functions and expressed in the form of a fraction is a rational function. A rational fraction is of the form f(x)/g(x), and g(x) ≠ 0. The functions used in this rational function can be an algebraic function or any other function. The graphical representation of these rational functions is similar to the asymptotes, since it does not touch the axis lines.
Signum Function
The signum function helps us to know the sign of the function and does not give the numeric value or any other values for the range. The range of the signum function is limited to {1, 0, 1}. For the positive value of the domain, the signum function gives an answer of 1, for negative values the signum function gives an answer of 1, and for the 0 value of a domain, the image is 0. The signum function has wide application in software programming.
Even and Odd Function
The even and odd functions are based on the relationship between the input and the output values of the function. For the negative domain value, if the range isa negative value of the range of the original function, then the function is an odd function. And for the negative domain value, if the range is the same as that of the original function, then the function is an even function.
If f(x) = f(x), for all values of x, then the function is an even function, and if f(x) = f(x), for all values of x, then the function is an odd function. An example of even functions are x^{2}, Cosx, Secx, and an example of odd functions are x^{3}, Sinx, Tanx.
Periodic Function
The function is considered a periodic function if the same range appears for different domain values and in a sequential manner. The trigonometric functions can be considered periodic functions. For example, the function f(x) = Sinx, have a range[1, 1] for the different domain values of x = nπ + (1)^{n}x. Similarly, we can write the domain and the range of the trigonometric functions and prove that the range shows up in a periodic manner.
Inverse function
The inverse of a function f(x) is denoted by f^{1}(x). For inverse of a function the domain and range of the given function is changedas the range and domain of the inverse function. The inverse of a function can be prominently seen in algebraic functions and in inverse trigonometric functions. The domain of Sinx is R and its range is [1, 1], and for Sin^{1}x the domain is [1, 1] and the range is R. The inverse of a function exists, if it is a bijective function.
If a function f(x) = x^{2}, then the inverse of the function is f^{1}(x) = \(\sqrt x\).
Greatest Integer Function
The greatest integer function is also known as the step function. The greatest integer function rounds up the number to the nearest integer less than or equal to the given number. Clearly, the input variable x can take on any real value. However, the output will always be an integer. Also, all integers will occur in the output set. Thus, the domain of this function is real numbers R, while its range isintegers (Z).
The greatest integer function graph is known as the step curve because of the step structure of the curve.The greatest integral function is denoted as f(x) = ⌊x⌋. For a function taking values from [1, 2), the value of f(x) is 1.
Composite Function
The composite functions are of the form of gof(x), fog(x), h(g(f(x))), and is made from the individual functions of f(x), g(x), h(x). The composite functions made of two functions have the range of one function forming the domain for another function. Let us consider a composite function fog(x), which is made up of two functions f(x) and g(x).
Here we write fog(x) = f(g(x)). The range of g(x) forms the domain for the function f(x). It can be considered as a sequence of two functions. If f(x) = 2x + 3 and g(x) = x + 1 we have fog(x) = f(g(x)) = f(x + 1) = 2(x + 1) + 3 = 2x + 5.
Types oF Functions  Based on Domain
Functions are used in all the other topics of maths. The functions have been classified based on the types of equations used to define the functions. The function equations generally have algebraic expressions, trigonometric functions, logarithms, exponents, and hence are named based on these domain values. The three broad types of functions based on domain value are as follows.
Algebraic Function
An algebraic function is helpful to define the various operations of algebra. The algebraic function has a variable, coefficient, constant term, and various arithmetic operators such as addition, subtraction, multiplication, division. An algebraic function is generally of the form of f(x) = a^{n}x^{n} + a^{n  1}x^{n  1}+ a^{n2}x^{n2}+ ....... ax + c.
The algebraic function can also be represented graphically. The algebraic function is also termed as a linear function, quadratic function, cubic function, polynomial function, based on the degree of the algebraic equation.
Trigonometric Functions
The trigonometric functions also have a domain and range similar to any other function. The six trigonometric functions are f(θ) = sinθ, f(θ) = cosθ, f(θ) = tanθ, f(θ) = secθ, f(θ) = cosecθ. Here the domain value θ is the angle and is in degrees or in radians. These trigonometric functions have been taken based on the ratio of the sides of a rightangle triangle, and are based on the Pythagoras theorem.
Further from these trigonometric functions, inverse trigonometric functions have also been derived. The domain of the inverse trigonometric function is a real number value and its range is an angle. The trigonometric functions and the inverse trigonometric functions are also sometimes referred to as periodic functions since the principal values are repeated.
Logarithmic Functions
Logarithmic functions have been derived from the exponential functions. The logarithmic functions are considered as the inverse of exponential functions. Logarithmic functions have a 'log' in the function and it has a base. The logarithmic function is of the form y = \(\log_ax \). Here the domain value is the input value of 'x' and is calculated using the Napier logarithmic table. The logarithmic function gives the number of exponential times to which the base has raised to obtain the value of x. The same logarithmic function can be expressed as an exponential function as x = a^{y}.
Related Topic
The following topic help in a better understanding of the types of functions.
 Functions
 What are Functions?
 Relations and Functions
 Graphing Functions
 Domain and Range of a Function
 Composite Functions
FAQs on Types of Functions
What are the Types of Functions in Maths?
The types of functions can be broadly classified into four types.
 Based on Element: One to one Function, many to one function, onto function, one to one and onto function, into function.
 Based on Domain: Algebraic Functions, Trigonometry functions, logarithmic functions.
 Based on Range: Modulus function, rational function, signum function, even and odd function, greatest integer function.
 Based on Equations: Identity function, linear function, quadratic function, cubic function, polynomial function.
How do you Determine the Types of Functions?
The types of functions can be determined based on the domain, range, and functional equation. Further classifying functions into types of functions helps to group and easily understand each of the types of functions. All the trigonometric functions can be grouped under periodic functions. Functions such as identity function, linear function, the quadratic, cubic function can be groupedunder polynomial functions. Thus the function equation y = f(x) is helpful todefine the type of function.
What Type of Functions is Always Continuous?
The functions which have a range for every input value of the domain can be termed as a continuous function. The simplest example of a continuous function is the identity function which has equal domain and range value. Other examples of continuous functions are the trigonometric sine function and cosine functions.
What are the Various Forms of Representation of Functions?
The functions are generally represented in the form of an equation y = f(x), where x is the domain and y or f(x) is the range of the function. The functions with the domain and range elements are also represented as venn diagrams or as roster form. In roster form the domain and range of the function are represented as {\((x_1, f(x_1)), (x_2, f(x_2)), (x_3, f(x_3))\)}.
What are the other math applications of Types of Functions?
The types of functions have enormous applications in algebra, trigonometry, logarithms, exponents. All the algebraic expressions can be counted as functions as it has an input domain value of x and the output range, which is the answer of the algebraic function. The trigonometric functions also have the angle value as the domain and range value.
Can any Math Equation be Considered a Function?
Yes. A math equation that is not equal to zero can be considered as a function. Alternatively, a math equation with two variables where one variable can be taken as a domain and the other variable can be taken as the range, can be called a function.
What are the applications of types of functions?
The types of functions havenumerous applications in physics, engineering, computer sciences, artificial intelligence. All of these fields aim at connecting one set of data points (domain) to another set of data points(range). Also, the functions help in representing the huge set of data points in a simple mathematical expression of the formal y = f(x).
FAQs
What are the 4 types of functions? ›
 Functions with arguments and return values. This function has arguments and returns a value: ...
 Functions with arguments and without return values. ...
 Functions without arguments and with return values. ...
 Functions without arguments and without return values.
An example of a simple function is f(x) = x^{2}. 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) = x^{2} + 3, f(x) = 1/x, f(x) = 2x + 3, etc.
What are the 12 types of functions? › Quadratic. f(x)=x^2. D: ∞,∞ R: 0,∞
 Reciprocal. f(x)=1/x. D: ∞,0 U 0,∞ R: ∞,0 U 0,∞ Odd.
 Exponential. f(x)=e^x. D: ∞,∞ R: 0,∞
 Sine. f(x)=SINx. D: ∞,∞ R: 1,1. Odd.
 Greatest Integer. f(x)= [[x]] D: ∞,∞ R: {All Integers} Neither.
 Absolute Value. f(x)= I x I. D: ∞,∞ R: 0,∞ ...
 Linear. f(x)=x. Odd.
 Cubic. f(x)=x^3. Odd.
 The Name  describes the purpose of the function. ...
 The Inputs  called parameters. ...
 The Calculation  varies for each function.
 The Output  Usually one (but sometimes zero or sometimes many) values that are calculated inside the function and "returned" via the output variables.
Ans. 2 The different types of functions are as follows: many to one function, one to one function, onto function, one and onto function, constant function, the identity function, quadratic function, polynomial function, modulus function, rational function, signum function, greatest integer function and so on.
A technical definition of a function is: a relation from a set of inputs to a set of possible outputs where each input is related to exactly one output.
What is the definition of a function? ›noun. the kind of action or activity proper to a person, thing, or institution; the purpose for which something is designed or exists; role. any ceremonious public or social gathering or occasion. a factor related to or dependent upon other factors: Price is a function of supply and demand.
function, in mathematics, an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable (the dependent variable).
What are the 10 basic functions? › y=x^2. Squaring.
 y=x^3. Cubing.
 y=x Absolute Value.
 y=1/x. Reciprocal.
 y=sin(x) Sine.
 y=cos(x) Cosine.
 y=e^x. Exponential Growth.
 y=ln(x) Natural Log.
 One – one function (Injective function)
 Many – one function.
 Onto – function (Surjective Function)
 Into – function.
 Polynomial function.
 Linear Function.
 Identical Function.
 Quadratic Function.
What are basic functions? ›
Basic Functions and Their Inverses. Definition. A function is a rule that assigns to every x value in the domain, one and only one y value in the range. Definition. A function is onetoone if for every y value in the range, there is one and only one x value such that f(x) = y.
The eight types are linear, power, quadratic, polynomial, rational, exponential, logarithmic, and sinusoidal.
What is a function 7th grade? ›A function is a rule that is performed on a number, called an input, to produce a result called an output. The rule consists of one or more mathematical operations that are performed on the input. An example of a function is y = 2x + 3, where x is the input and y is the output.
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 are elements of function? ›Functions consist of four components: Input parameters. Output parameters. Return value. Math section.
You can use the vertical line test on a graph to determine whether a relation is a function. If it is impossible to draw a vertical line that intersects the graph more than once, then each xvalue is paired with exactly one yvalue. So, the relation is a function.
How do you find a definition? ›...
Basic Definitions
 Webster's New World Medical Dictionary.
 The AMA Dictionary of Business and Management.
 Dictionary of Social Work.
Quite often when carrying out a project, some set of tasks will need to be repeated with different input. To ensure that the analyses are carried out the same way each time, it is important to wrap the code into a named function that is called each time it's needed.
Why function definition is important? ›Function declarations are important because a calling convention (part of the ABI of a platform) can define different places for arguments and return values based on the types a function returns and accepts as arguments.
3. Where is function defined? Explanation: Functions can be defined inside a module, a class or another function.
Who is the first define function? ›
The term "function" was introduced by Gottfried Wilhelm Leibniz (16461716) almost fifty years after the publication of Geometry. The idea of a function was further formalized by Leonhard Euler (pronounced "oiler" 17071783) who introduced the notation for a function, y = f(x).
A function is an equation that has only one answer for y for every x. A function assigns exactly one output to each input of a specified type. It is common to name a function either f(x) or g(x) instead of y. f(2) means that we should find the value of our function when x equals 2. Example.
What is a function in algebra simple? ›A function relates an input to an output. It is like a machine that has an input and an output. And the output is related somehow to the input. f(x) "f(x) = ... " is the classic way of writing a function.
 Linear Function: f(x) = mx + b.
 Square Function: f(x) = x^{2}
 Cube Function: f(x) = x^{3}
 Square Root Function: f(x) = √x.
 Absolute Value Function: f(x) = x
 Reciprocal Function. f(x) = 1/x.
Which of the basic functions are even, which are odd and which are neither? Even Functions: The squaring function and the absolute value function. Odd Functions: The identity function, the cubing function, the reciprocal function, the sine function.
The types of functions can be broadly classified into four types. Based on Element: One to one Function, many to one function, onto function, one to one and onto function, into function. Based on Domain: Algebraic Functions, Trigonometry functions, logarithmic functions.
What are the 5 operations of functions? › The sum of two functions, f and g: (f + g)(x) = f (x) + g(x).
 The difference of two functions f and g: (f  g)(x) = f (x)  g(x).
 The product of two functions f and g: (fg)(x) = f (x)×g(x).
 The quotient of two functions f and g: ( )(x) = . If g(x) = 0, the quotient is undefined.
 Linear. f (x) = mx + b, m ≠ 0. D: (∞, ∞) R: (∞, ∞) ...
 Constant. f (x) = c. D: (∞, ∞) R: [c, c} or {c} ...
 Identity. f (x) = x. D: (∞, ∞) R: (∞, ∞) ...
 Square. f (x) = x^2. D: (∞, ∞) R: [0, ∞) ...
 Cube. f (x) = x^3. ...
 Square Root. f(x) = sqrt(x) = x^(1/2) ...
 Cube Root. f(x) = cuberoot(x) = x^(1/3) ...
 Absolute Value. f(x) = x
 Promotion. Promotion fosters brand awareness while educating target audiences on a brand's products or services. ...
 Selling. ...
 Product management. ...
 Pricing. ...
 Marketing information management. ...
 Financing. ...
 Distribution.
Functions enable programmers to break down or decompose a problem into smaller chunks, each of which performs a particular task. Once a function is created, the details of how it works can almost be forgotten about.
What is a function 9th grade? ›
1 — Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output.
 Linear Functions.
 Square Functions.
 Cubic Functions.
 Square root functions.
 Quadratic Functions.
 Reciprocal Functions.
 Logarithmic Functions.
 Absolute Value Functions.
Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output.
Vertical lines are not functions. The equations y = ± x and x 2 + y 2 = 9 are examples of nonfunctions because there is at least one value with two or more values.
What grade math is functions? ›Functions  Grade 8  Common Core Math  CK12 Foundation. Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output.
A function is the relationship between an input and an output.
How do you graph a function? ›To graph a function, you have to select xvalues and plug them into the equation. Once you plug those values into the equation, you will get a yvalue. Your xvalues and your yvalues make up your coordinates for a single point.
 declarative.
 interrogative.
 imperative.
 exclamative.
 Algebraically.
 Numerically.
 Visually.
 Verbally.
 Linear Function: f(x) = mx + b.
 Square Function: f(x) = x^{2}
 Cube Function: f(x) = x^{3}
 Square Root Function: f(x) = √x.
 Absolute Value Function: f(x) = x
 Reciprocal Function. f(x) = 1/x.
What are the four 4 general functions of language? ›
The four basic functions of language are based on the goal of that communication: expressing observations, expressing thoughts, expressing feelings, and expressing needs.
Simple Sentences
Examples of simple sentences include the following: Joe waited for the train. The train was late. Mary and Samantha took the bus.
 Complex Sentences.
 Simple Sentences.
 Compound Sentences.
 Declarative Sentence.
 Exclamatory Sentences.
 Imperative Sentence.
 Interrogative Sentences.
There are four types of sentences: simple, compound, complex, and compoundcomplex. Each sentence is defined by the use of independent and dependent clauses, conjunctions, and subordinators.
What are the 3 types of function *? ›Types of Functions
Many – one function. Onto – function (Surjective Function) Into – function. Polynomial function.