Q.

For the set A = {1, 2, 3}, define a relation R in the set A as follows:

            R = {(1, 1), (2, 2), (3, 3), (1, 3)}

Then, the ordered pair to be added to R to make it the smallest equivalence relation is:

1 (1, 3)  
2 (3, 1)  
3 (2, 1)  
4 (1, 2)  

Ans.

(2)

Ans.    (3, 1)

Explanation:

(1,1), (2,2) and (3,3)∈R

⇒R is reflexive.

                            (1,3)∈R

                            (1,3)∈R but (3,1)∉R

⇒R is not symmetric.

To make R an equivalence relation, we can add (3, 1).

Clearly, R is reflexive and transitive. For R to be symmetric, we should add (3, 1) in R.