हिंदी

R is a Relation on the Set Z of Integers and It is Given by (X, Y) ∈ R ⇔ | X − Y | ≤ 1. Then, R is (A) Reflexive and Transitive (B) Reflexive and Symmetric (C) Symmetric and Transitive (D) an Equiv

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प्रश्न

R is a relation on the set Z of integers and it is given by
(x, y) ∈ R ⇔ | x − y | ≤ 1. Then, R is ______________ .

विकल्प

  • Reflexive and transitive

  • Reflexive and symmetric

  • Symmetric and transitive

  • an equivalence relation

MCQ
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उत्तर

Reflexive and symmetric

Reflexivity: Let x∈R. Then,

x−x=0 < 1

⇒ |x−x | ≤ 1

⇒(x, x) ∈ R for all x ∈ Z

So, R is reflexive on Z.

Symmetry : Let (x, y)∈R. Then,

| x−y | ≤ 0

⇒ |−(y−x) | ≤ 1

⇒ | y−x | ≤ 1         [ Since |x−y|=|y−x| ]

⇒ (y, x) ∈ R for all x, y ∈ Z

So, R is symmetric on Z.

Transitivity : Let (x, y) ∈ R and ( y, z ) ∈ R. Then,

| x−y | ≤ 1 and | y−z | ≤ 1

⇒ It is not always true that |x−y| ≤ 1.

⇒ (x, z) ∉ R

So, R is not transitive on Z.

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अध्याय 1: Relations - Exercise 1.4 [पृष्ठ ३१]

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आर.डी. शर्मा Mathematics Volume 1 and 2 [English] Class 12
अध्याय 1 Relations
Exercise 1.4 | Q 3 | पृष्ठ ३१

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