Check sibling questions

Examples

Example 1

Example 2

Example 3

Example 4 Important

Example 5

Example 6 Important

Example 7

Example 8 Important

Example 9

Example 10

Example 11 Important

Example 12 Important

Example 13 Important

Example 14 Important

Example 15 Deleted for CBSE Board 2023 Exams

Example 16 Deleted for CBSE Board 2023 Exams

Example 17 Deleted for CBSE Board 2023 Exams

Example 18 Important Deleted for CBSE Board 2023 Exams

Example 19 Important Deleted for CBSE Board 2023 Exams

Example 20 Deleted for CBSE Board 2023 Exams

Example 21 Deleted for CBSE Board 2023 Exams

Example 22 Deleted for CBSE Board 2023 Exams

Example 23 Important Deleted for CBSE Board 2023 Exams

Example 24 Deleted for CBSE Board 2023 Exams

Example 25 Important Deleted for CBSE Board 2023 Exams

Example 26 Deleted for CBSE Board 2023 Exams

Example 27 Important Deleted for CBSE Board 2023 Exams

Example 28 (a) Deleted for CBSE Board 2023 Exams

Example 28 (b)

Example 28 (c)

Example 29 Deleted for CBSE Board 2023 Exams

Example 30 Deleted for CBSE Board 2023 Exams

Example 31 Important Deleted for CBSE Board 2023 Exams

Example 32 Deleted for CBSE Board 2023 Exams

Example 33 Deleted for CBSE Board 2023 Exams

Example 34 Deleted for CBSE Board 2023 Exams

Example 35 Deleted for CBSE Board 2023 Exams

Example 36 Deleted for CBSE Board 2023 Exams

Example 37 Important Deleted for CBSE Board 2023 Exams

Example 38 Deleted for CBSE Board 2023 Exams

Example 39 Deleted for CBSE Board 2023 Exams

Example 40 Deleted for CBSE Board 2023 Exams

Example 41 You are here

Example 42 Important

Example 43 Important

Example 44

Example 45 (a) Deleted for CBSE Board 2023 Exams

Example 45 (b) Deleted for CBSE Board 2023 Exams

Example 46 Important

Example 47 Important

Example 48 Important

Example 49

Example 50

Example 51 Important

Chapter 1 Class 12 Relation and Functions
Serial order wise

Example 41 - If R1, R2 are equivalence relations in set A

Example 41 - Chapter 1 Class 12 Relation and Functions - Part 2
Example 41 - Chapter 1 Class 12 Relation and Functions - Part 3 Example 41 - Chapter 1 Class 12 Relation and Functions - Part 4

Get live Maths 1-on-1 Classs - Class 6 to 12


Transcript

Example 41 If R1 and R2 are equivalence relations in a set A, show that R1 ∩ R2 is also an equivalence relation. R1 is an equivalence relation 1. R1 is symmetric (a, a) ∈ R1, for all a ∈ A. 2. R1 is reflexive If (a, b) ∈ R1 , then (b, a) ∈ R1 3. R1 is transitive If (a, b) ∈ R1 & (b, c) ∈ R1 , then (a, c) ∈ R1 R2 is an equivalence relation 1. R2 is symmetric (a, a) ∈ R2, for all a ∈ A. 2. R2 is reflexive If (a, b) ∈ R2 , then (b, a) ∈ R2 3. R2 is transitive If (a, b) ∈ R2 & (b, c) ∈ R2 , then (a, c) ∈ R2 We have to prove R1 ∩ R2 is equivalence relation Check reflexive For all a ∈ A (a, a) ∈ R1, & (a, a) ∈ R2 Hence, (a, a) ∈ both R1 & R2 Hence, (a, a) ∈ R1 ∩ R2 ∴ R1 ∩ R2 is reflexive. Check symmetric R1 is symmetric ,hence If (a, b) ∈ R1 , then (b, a) ∈ R1 R2 is symmetric, hence If (a, b) ∈ R2 , then (b, a) ∈ R2 From (1) and (2) If (a, b) ∈ R1 ∩ R2, then (b, a) ∈ R1 ∩ R2 Hence , R1 ∩ R2 is symmetric. Checking transitive R1 is transitive, Hence, if (a, b) ∈ R1 & (b, c) ∈ R1 , then (a, c) ∈ R1 R2 is transitive, Hence, if (a, b) ∈ R2 & (b, c) ∈ R2 , then (a, c) ∈ R2 From (3) & (4) If (a, b) ∈ R1 ∩ R2 and (b, c) ∈ R1 ∩ R2 , then (a, c) ∈ R1 ∩ R2, ∴ R1∩ R2 is transitive. Thus, R1 ∩ R2 is an equivalence relation.

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 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.