JEE Previous Year Question

Let ={(a,b) NxN:|a-b|13}and
={(a,b) NxN: |a-b|13}. Then on N:

Topic: JEE PYQ

Answer: B. Full step-by-step solution below.

  1. ABoth and are equivalence relations
  2. BNeither nor is an equivalence relation
  3. C is an equivalence relation but is not
  4. D is an equivalence relation but is not

Correct answer: B

Solution

(b) {(a,b) NxN: |a-b|13}
R2={(a,b) NxN:|a-b|13}.
For :
(i) Reflexive relation
(a,a) NxN: |a-a|13
(ii) Symmetric relation

(iii) Transitive relation

but
For R2:
(i) Reflexive relation
(a,a) NxN:|a-a|13
(ii) Symmetric relation
(b,a) NxN:|b-a|13
(iii) Transitive relation
(a,b) R2,(b,c) R2,(a,c) R2
(1, 3) R2, (3, 14) R2 but (1, 14) R2

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