f: A -> B

A relation from A to B is a function if every element of set A has one and only one image in set B.


∴ For a function

  1. Every element of set A will have an image.
  2. Every element of set A will only one image in set B

Let us take an example

Let A = {a, b, c, d}

and B = {Aman, Ankit, Baljinder, Chandu, Eklavya}


Check if the following are functions?

Function - Example 1.jpg

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Function - Example 2.jpg

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Function - Example 3.jpg

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Note : In a function, domain will always be equal to first set.

Function - Example 4.jpg

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  1. Chapter 1 Class 12 Relation and Functions
  2. Concept wise

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.