For real numbers x and y, define x R y iff x – y+ √2 is an irrational number. Then the relation R is

R: x R y is irrational.

Since, x-x=0 always, therefore is irrational. Hence, (x, x)R x R. Hence, R is reflexive.


R is not symmetric. Proof by counter-example:


Let . Then is irrational, Therefore (x, y)R. But


is rational, therefore (y, x)R. Hence, R is not symmetric.


R is not transitive. Proof by counter-example:


Let and , then


is irrational, therefore (x, y)R


is irrational, therefore (y, z)R


is rational, therefore (x, z)R. Hence, R is not transitive.

1