Q. 84.7( 9 Votes )

# Let A = {1, 2} and B={3, 4}. Find the total number of relations from A into B.

Answer :

Given,

A= {1, 2}, B= {3, 4}

n(A) = 2 (Number of elements in set A).

n(B) = 2 (Number of elements in set B).

We know,

n(A × B) = n(A) × n(B) = 2 × 2 = 4

∴ Number of relations from A to B are 4.

__NOTE:__

Given,

A= {1, 2}, B= {3, 4}

A relation from A to B can be defined as:

A × B = {(1, 3), (1, 4), (2, 3), (2, 4)}

∴ Number of relations from A to B are 4

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