COMEDK2022MathematicsSets and Relations
If A= 3,5,7 and B= 1,2,3,5 , then A B B A is equal to
Options
- A(3,3),(5,3),(2,7),(7,2)
- B(3,3),(3,5),(5,3),(5,5)
- C(3,3),(5,5)
- D(3,5),(5,5),(5,3)
Correct answer
B. (3,3),(3,5),(5,3),(5,5)
Step-by-step solution
The set A B consists of all ordered pairs (a, b) where a A and b B . Given A = 3, 5, 7 and B = 1, 2, 3, 5 , the elements of A B are pairs (a, b) such that a 3, 5, 7 and b 1, 2, 3, 5 . The set B A consists of all ordered pairs (b, a) where b B and a A . The elements of B A are pairs (b, a) such that b 1, 2, 3, 5 and a 3, 5, 7 . The intersection A B B A contains pairs (x, y) that belong to both A B and B A . This implies x A and x B , and y A and y B . The intersection of sets A and B is A B = 3, 5, 7 1, 2, 3, 5 = 3,