Question
Write down all the subsets of the following sets
(i) {a} (ii) {a, b} (iii) {1, 2, 3} (iv) φ
Solution
(a) A = {a}
Number of elements in set A = 1
Number of subsets = 21 = 2
∴ The subsets are φ, {a}
(b) A = {a, b}
Number of elements in set A = 2
Number of subsets = 22 = 4
∴ The subsets are φ, {a}, {b}, {a, b}
(c) A = {1, 2, 3}
Number of elements in set A = 3
Number of subsets = 23 = 8
∴ The subsets are φ, {1}, {2}, {3}, {1, 2}, {2, 3}, {1, 3} and {1, 2, 3}
(d) φ = { }
Number of elements = 0
Number of subsets = 20 = 1
∴ The subsets is φ
