Q.

For real numbers x and y, define xRy if and only if x-y+2 is an irrational number. Then the relation R is:

1 reflexive  
2 symmetric  
3 transitive  
4 equivalence  

Ans.

(1)

Ans.      reflexive

Explanation:

Rx=x-x+2=2 is an irrational number.

Thus, R is reflexive.

Also, (2,1)∈R  as  2-1+2=22-1 is an irrational number, but (1,2)∉R  as  1-2+2=1 is a rational number. So R is not symmetric. Since, R21  and  R22  but 1 is not related to 2. So, R is not transitive.