Which of the following pairs of sets are disjoint?
(i) {1, 2, 3, 4} and {x : x is a natural number and 4 ≤x≤6}
(ii) {a, e, i, o, u} and {b, c, d, f}
(iii) {x : x is an even integer} and {x : x is an odd integer}
(i) Let A = {1, 2, 3, 4}
and B = {x : x is a natural number and 4 ≤x≤6}
= {4, 5, 6}
∴ A∩B = {1, 2, 3, 4} ∩ {4, 5, 6}
= {4}
Hence A and B are not disjoint.
(ii) Let A = {a, e, i, o, u}
and B = {b, c, d, f}
∴ A∩B=Φ
Hence A and B are disjoint.
(iii) Let A = {x : x is an even integer}
and B = {x : x is an odd integer}
∴ A∩B=Φ
Hence A and B are disjoint.