NCERT Class XI Mathematics - Relations and Functions - Solutions

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Question : 18
Total: 36
Let A = {x, y, z} and B = {1, 2}. Find the number of relations from A to B.
Solution:  
Given A = {x, y, z} and B = {1, 2}
∴ n(A) = 3 & n(B) = 2
Since n(A × B) = n(A) × n(B)
∴ n(A × B) = 3 × 2 = 6
Number of relations from A to B is equal to the number of subsets of A × B.
Since A × B contains 6 elements.
⇒ Number of subsets of A × B = 26 = 64
So, there are 64 relations from A to B.
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