Number of elements of A × B = Number of Elements of A  ×  Number of elements of B

 

So, if set A has 3 elements, set B has 2 elements

Number of elements of A × B = 3 × 2 = 6

 

Let us check

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

A  × B = {(1, 3), (1, 4),

        (2, 3), (2, 4),

        (3, 3), (3, 4)}

Number of elements of A × B = 6

 

If A × A has 9 elements, then how many elements does set A have?

We know that

Number of elements of A × A = Number of Elements of A  ×  Number of elements of A

Number of elements of A × A = (Number of elements of A) 2

9 = (Number of elements of A) 2

(Number of elements of A) 2 = 9

Number of elements of A = √9 = 3

  1. Chapter 2 Class 11 Relations and Functions
  2. Concept wise
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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 7 years. He provides courses for Mathematics and Science from Class 6 to 12. You can learn personally from here https://www.teachoo.com/premium/maths-and-science-classes/.
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