Let R be the set of real numbers: Statement 1 : A = {(x, y) ∈ R × R : y - x is an integer} is an equivalence relation on R. Statement 2 : B = {(x, y) ∈ R × R : x = αy for some rational number α} is an equivalence relation of R |
Statement 1 is true, Statement 2 is false Statement 1 is false, Statement 2 is true Statement 1 is true, Statement 2 is true ; Statement 2 is a correct explanation for Statement 1 Statement 1 is true, Statement 2 is true ; Statement 2 is not correct explanation for Statement 1 |
Statement 1 is true, Statement 2 is false |
Since x - x = 0 ∈ Z, (x, x) ∈ A ⇒ A is reflexive $(x, y) ∈ A ⇒ x - y ∈ z ⇒ y - x ∈ z$ $⇒(y,x)∈ A⇒A$ is symmetric $(x, y) ∈ A, (y, z) ∈ A ⇒ x - y ∈ z, y - x ∈ z$ $⇒x-z∈ z⇒(x, z)∈ A$ ⇒ A is equivalence relation $(0, 1) ∈ B ∵ 0 = (0)(1), 0 ∈ ..... δ$ But (1, 0) ∉ B ⇒ B is not symmetric ⇒ B is not equivalence. |