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Let A = {x ϵ W : x < 2}, B = {x ϵ N : 1 < x ≤ 4} and C = {3, 5}. Verify that: (i) A × (B ∪ C) = (A × B) ∪ (A × C) (ii) A × (B ∩ C) = (A × B) ∩ (A × C) |
Answer» (i) Given: A = {x ϵ W : x < 2} Here, W denotes the set of whole numbers (non – negative integers). ∴ A = {0, 1} [∵ It is given that x < 2 and the whole numbers which are less than 2 are 0 & 1] B = {x ϵ N : 1 < x ≤ 4} Here, N denotes the set of natural numbers. ∴ B = {2, 3, 4} [∵ It is given that the value of x is greater than 1 and less than or equal to 4] and C = {3, 5} L. H. S = A × (B ⋃ C) By the definition of the union of two sets, (B ⋃ C) = {2, 3, 4, 5} = {0, 1} × {2, 3, 4, 5} Now, by the definition of the Cartesian product, Given two non – empty sets P and Q. The Cartesian product P × Q is the set of all ordered pairs of elements from P and Q, .i.e. P × Q = {(p, q) : p Є P, q Є Q} = {(0, 2), (0, 3), (0, 4), (0, 5), (1, 2), (1, 3), (1, 4), (1, 5)} R. H. S = (A × B) ⋃ (A × C) Now, A × B = {0, 1} × {2, 3, 4} = {(0, 2), (0, 3), (0, 4), (1, 2), (1, 3), (1, 4)} and A × C = {0, 1} × {3, 5} = {(0, 3), (0, 5), (1, 3), (1, 5)} Now, we have to find (A × B) ⋃ (A × C) So, by the definition of the union of two sets, (A × B) ⋃ (A × C) = {(0, 2), (0, 3), (0, 4), (0, 5), (1, 2), (1, 3), (1, 4), (1, 5)} = L. H. S ∴ L. H. S = R. H. S is verified (ii) Given: A = {x ϵ W : x < 2} Here, W denotes the set of whole numbers (non – negative integers). ∴ A = {0, 1} [∵ It is given that x < 2 and the whole numbers which are less than 2 are 0, 1] B = {x ϵ N : 1 < x ≤ 4} Here, N denotes the set of natural numbers. ∴ B = {2, 3, 4} [∵ It is given that the value of x is greater than 1 and less than or equal to 4] and C = {3, 5} L. H. S = A × (B ⋂ C) By the definition of the intersection of two sets, (B ⋂ C) = {3} = {0, 1} × {3} Now, by the definition of the Cartesian product, Given two non – empty sets P and Q. The Cartesian product P × Q is the set of all ordered pairs of elements from P and Q, .i.e. P × Q = {(p, q) : p Є P, q Є Q} = {(0, 3), (1, 3)} R. H. S = (A × B) ⋂ (A × C) Now, A × B = {0, 1} × {2, 3, 4} = {(0, 2), (0, 3), (0, 4), (1, 2), (1, 3), (1, 4)} and A × C = {0, 1} × {3, 5} = {(0, 3), (0, 5), (1, 3), (1, 5)} Now, we have to find (A × B) ⋂ (A × C) So, by the definition of the intersection of two sets, (A × B) ⋂ (A × C) = {(0, 3), (1, 3)} = L. H. S ∴ L. H. S = R. H. S is verified |
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