R is a relation on the set Z of integers and it is given by $(x, y) ∈R⇔|x -y | ≤1$. Then, R is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → reflexive and symmetric
For any $x ∈ Z$, we have
$|x-x|=0≤1$
$∴|x-x|≤1$ for all $x ∈ Z$
$⇒(x, x) ∈ R$ for all $x ∈ Z$
⇒ R is reflexive on Z.
Let $(x, y) ∈ R$. Then,
$|x-y|≤1⇒|y-x|≤1⇒ (y, x) ∈ R$
Thus, $(x, y) ∈ R⇒(y, x) ∈ R$
So, R is a symmetric relation on Z.
We observe that $(1, 0) ∈ R$ and $(0, -1) ∈ R$, but $(1, -1) ∉ R$.
So, R is not a transitive relation on Z.