U 12345 A 123 B 245 C 347 determine A Times B B Times A

U = {1,2,3,4,5}, A = {1,2,3}, B = {2,4,5}, C = {3,4,7}, determine A Times B, B Times A A Times B = number of relations from A to B

Solution

AxB = {(1,2)(1,4)(1,5)(2,2)(2,4)(2,5)(3,2)(3,4)(3,5)}

AXB means all possible mapping from an element in A to an element in B

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|AXB} = no of relations from A to B = 3x3 = 9

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BxA = An element from B is the first in ordered pair, and from A second ordered pair

= {(2,1)(2,2)(2,3)(4,1)(4,2)(4,3)(5,1)(5,2)(5,3)}