Read pages 24-25 Example 1 in your textbook, Principles of Mathematics 12 .

Complete the Your Turn question on page 25 related to the union and intersection of two sets.

Click here to verify your answers .

Now that you have been introduced to the concept of intersection and union of sets, consider the various types of problems you can solve using these concepts.

 

Given A = { x – 10 x 10, x is an even integer} and B = { x |0 x 10, x I} , draw a Venn diagram to represent A and B . Then, determine A B , n ( A B ), A B , n ( A B ).

 

A represents all the even integers including and between -10 and 10.

B represents all the integers including and between 0 and 10.

The elements that are in both of these sets are A B = {0, 2, 4, 6, 8, 10}.

 

Recall from Lesson 1A that n ( A ) represents the number of elements in the set A . Similarly, n ( A B ) represents the number of elements in the intersection of A and B .

In this example, 6 elements are in the intersection of sets A and B so n ( A B ) = 6.

The union of A and B , A B , is the elements in A or B or both of these sets.

A B = {-10, - 8, -6, - 4, - 2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

By counting, you can see that n ( A B ) = 16.