Finding Inverse

Inverse of function: Proof questions →
Chapter 1 Class 12 Relation and Functions
Concept wise

How to find Inverse?

Last updated at April 16, 2024 by

We find inverse in two scenarios

  1. When f is given as set
  2. When f is given as a function

 

When f is given as set

f = {(1, 4), (2, 5), (3, 6)}

 

In f -1 ,

We reverse all the elements

(1, 4) becomes (4, 1)

(2, 5) becomes (5, 2)

(3, 6) becomes (6, 3)

 

∴ f -1 = {(4, 1), (5, 2), (6, 3)}

 

When f is given as

 f(x) = 2x + 1

 

We put f(x) = y

and find y in terms of x

 

f(x) = 2x + 1

y = 2x + 1

y – 1 = 2x

2x = y – 1

x = (y - 1)/2

 

∴ f -1  = (y - 1)/2

To summarise finding inverse.jpg

 

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.