Types of Functions – Types, Definition and Examples

Functions are relationships in which each input leads to a specific output. In this lesson, the fundamentals of functions in mathematics, as well as the many types of functions, are addressed through the use of various examples to facilitate greater understanding. 

Functions: 

It is possible to think of functions as relationships between a set of possible inputs and a set of possible outputs. A function has the property that each input is related to exactly one output. In the case where A and B are any two non-empty sets, a function mapping from A to B will exist only if every element in set A has one end and only one image in set B. 

According to yet another definition, a function is defined as a relation “f” in which each element of a set “A” is mapped to exactly one element of another set (“B”). In addition, there can’t be two pairs with the identical initial element in a function at the same time. 

Representation of functions: 

The representation of functions can be represented in three different ways. It is necessary to depict the functions in order to demonstrate the domain values, the range values, and the relationship between these values. Venn diagrams, graphical formats, and roster forms are all effective tools for representing functions. 

Types of functions: 

In mathematics, there are several different types of functions, each of which is explored in greater depth below. The following are the many sorts of functions addressed in this section: 

• One – one function (Injective function)
• Many – one function
• Onto – function (Surjective Function)
• Into – function
• Polynomial function
• Linear Function
• Identical Function
• Quadratic Function
• Rational Function
• Algebraic Functions
• Cubic Function
• Modulus Function
• Signum Function
• Greatest Integer Function
• Fractional Part Function
• Even and Odd Function
• Periodic Function
• Composite Function
• Constant Function
• Identity Function 

One – one function (Injective function): 

One – one functions are defined as functions in which each element in the domain of the function has a separate image in the co-domain, and the function is defined as one – one functions. 

For example: R given by f(x) = 3x + 5 is one – one.

Many – one function: 

On the other hand, if there are at least two elements in the domain whose pictures are the same, the function is referred to as many to one in this context. 

For example f : R R given by f(x) = x² + 1 is many one.  

Onto – function (Surjective Function): 

When each element in the co-domain has at least one pre – image in the domain, a function is referred to as an onto function. 

Into – function: 

In the event that there is at least one element in the co-domain that is not a mirror image of any element in the domain, the function will be classified as an Into operation. 

Polynomial function: 

A real valued function f : P → P defined by 

y = f (a)= h₀ + h₁a + …….. + hₙaⁿ, 

Where n ∈ N, and 

h₀ + h₁ + ………. + hₙ ∈ P, 

for each a ∈ P, is called a polynomial function. 

• N is a positive integer that is not less than zero.
• The degree of a polynomial function is the power of the expression that has the highest value.
• When the degree is zero, the function is referred to as a constant function.
• If the degree is one, the function is referred to as a linear function. As an illustration, consider the expression b = a+1.
• Graph type: A straight line is always used.

As a result, a polynomial function can be written as: 

f(x) = aₙxⁿ + aₙ₋₁xⁿ⁻¹ + ……. + a₁x¹ + a0 

The degree of the polynomial function is defined as the power of the expression that has the highest value. The following are the various types of polynomial functions based on their degree:

• If the degree of the polynomial function is zero, the function is referred to as a Constant function. 
• If the degree of the polynomial function is one, it is referred to as a Linear function. 
• If the degree of the polynomial function is two, the function is called Quadratic. 
• If the degree of the polynomial function is three, the function is Cubic. 

Linear function: 

All functions of the form ax + b, where a, b ∈ R. 

Linear functions are defined as those with a value less than zero. A straight line will be drawn on the graph. In other terms, a linear polynomial function is a first-degree polynomial function in which the input must be multiplied by m and added to c in order to be considered linear. It can be stated mathematically as f(x) = mx + c.

Identical function: 

When two functions f and g are identical, the term “identical” is used. 

• The domain of f = domain of g
• The range of f = the Range of g 
• f(x) = g(x) ∀ x ∈ D_f and D_g 

Algebraic functions: 

An algebraic equation is a function that is composed of a finite number of terms including powers and roots of the independent variable x, as well as fundamental operations like addition, subtraction, multiplication, and division. 

Even and odd function: 

If f(x) = f(-x), the function will be an even function; if f(x) = -f(-x), the function will be an odd function. 

Conclusion: 

Domain, range, and function expression all have a role in determining the types of functions available. The expression that was used to define the function is the most important aspect in defining a function. The relationship between the items of the domain set and the elements of the range set, in addition to accounting for expression, also accounts for the kind of function. The classification of functions makes it easier to grasp and learn about the various sorts of functions available.