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Let f: A → B and g: B → C be the bijective functions. Then (g o f)–1 is ______.

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Question

Let f: A → B and g: B → C be the bijective functions. Then (g o f)–1 is ______.

Options

  • f –1 o g–1

  • f o g

  • g–1 o f–1

  • g o f

MCQ
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Solution

Let f: A → B and g: B → C be the bijective functions. Then (g o f)–1 is f –1 o g–1. 

Explanation:

Given that, f: A  → B and g: B → C be the bijective functions.

(f –1 o g–1) o (g o f) = f –1 o (g–1 o g o f)

= f –1 o (g–1 o g) o f  ......(As composition of functions is associative)

= f –1 o IB o f)  .......(Where IB is identity function on B)

= (f –1 o IB) o f

= f –1 o f

= IA

Thus (g o f)–1 = f –1 o g –1

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Chapter 1: Relations And Functions - Exercise [Page 15]

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NCERT Exemplar Mathematics Exemplar [English] Class 12
Chapter 1 Relations And Functions
Exercise | Q 41 | Page 15

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