

InterviewSolution
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Prove that:(i) (A ∪ B) x C = (A x C) = (A x C) ∪ (B x C)(ii) (A ∩ B) x C = (A x C) ∩ (B x C) |
Answer» (i) (A ∪ B) x C = (A x C) = (A x C) ∪ (B x C) Suppose (x, y) be an arbitrary element of (A ∪ B) × C (x, y) ∈ (A ∪ B) C Here, (x, y) are elements of Cartesian product of (A ∪ B) × C x ∈ (A ∪ B) and y ∈ C (x ∈ A or x ∈ B) and y ∈ C (x ∈ A and y ∈ C) or (x ∈ Band y ∈ C) (x, y) ∈ A × C or (x, y) ∈ B × C (x, y) ∈ (A × C) ∪ (B × C) … (1) Suppose (x, y) be an arbitrary element of (A × C) ∪ (B × C). (x, y) ∈ (A × C) ∪ (B × C) (x, y) ∈ (A × C) or (x, y) ∈ (B × C) (x ∈ A and y ∈ C) or (x ∈ B and y ∈ C) (x ∈ A or x ∈ B) and y ∈ C x ∈ (A ∪ B) and y ∈ C (x, y) ∈ (A ∪ B) × C … (2) From the equation 1 and 2, we get: (A ∪ B) × C = (A × C) ∪ (B × C) (ii) (A ∩ B) x C = (A x C) ∩ (B x C) Suppose (x, y) be an arbitrary element of (A ∩ B) × C. (x, y) ∈ (A ∩ B) × C Here, (x, y) are elements of Cartesian product of (A ∩ B) × C x ∈ (A ∩ B) and y ∈ C (x ∈ A and x ∈ B) and y ∈ C (x ∈ A and y ∈ C) and (x ∈ Band y ∈ C) (x, y) ∈ A × C and (x, y) ∈ B × C (x, y) ∈ (A × C) ∩ (B × C) … (1) Suppose (x, y) be an arbitrary element of (A × C) ∩ (B × C). (x, y) ∈ (A × C) ∩ (B × C) (x, y) ∈ (A × C) and (x, y) ∈ (B × C) (x ∈A and y ∈ C) and (x ∈ Band y ∈ C) (x ∈A and x ∈ B) and y ∈ C x ∈ (A ∩ B) and y ∈ C (x, y) ∈ (A ∩ B) × C … (2) From the equation (1) and (2), we get: (A ∩ B) × C = (A × C) ∩ (B × C) |
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