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.