
If A and B are any two sets, the set of all possible ordered pairs (a,b) with a Î A and b Î B, is called the cartesian product of A and B and is denoted by A ´ B. and it is read as A cross B. The set builder form of A ´ B is A ´ B = {(a,b)/a Î A and b Î B} Observing the above relation we find the following points. 1. The ordered pair of A ´ B, the first coordinate belongs to A while the second coordinate belongs to B. 2. A ´ B ¹ B ´ A. 3. If n(A)= a and n(B) = b then n(A ´ B) = ab. 4. If A is empty or B is empty then A ´ B is empty. 5. If one of the sets A and B is infinite the other is nonempty then A ´ B is also infinite.
Example:
(ii). B ´ A = {2,4} ´ {1,3,5}
(iii). n(A ´ B) = n(A) * n(B) Directions: Choose the correct answer. Also write at least 5 examples of your own. 