The Cartesian product A × A has 9 elements among which are found (–1, 0) and (0,1). Find the set A and the remaining elements of A × A.
Let A = {1, 2}, B = {1, 2, 3, 4}, C={5, 6} and D = {5, 6, 7, 8}. Verify that A x C is a proper subset of B x D.
A x C = {1, 2} x {5, 6} = {(1, 5), (1, 6), (2, 5), (2, 6)} ......(i)
B x D = {1, 2, 3, 4} x {5, 6, 7, 8}
= {(1, 5), (1, 6), (1, 7), (1, 8), (2, 5), (2, 6), (2, 7), (2, 8), (3, 5), (3, 6), (3, 7), (3, 8), (4, 5), (4, 6), (4, 7), (4, 8) .....(ii)
From (i) and (ii), we observe that every member of A x C is also a member of B x D
∴
Also, n(A x C) < n(B x D)
Hence,