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WORKBOOK

Example 31: (2009 MAT1): A and B are two sets. Which one is true for (A  B) \( A B).

 A) A A  B 
 B)A A  B 


C) A B   B A  The union of A-B and B-A is
called symmetric difference of

D) A B   B A  A and B and denoted by A Δ B. ,

E) A B  A B  A Δ B = (A – B) ∪ (B – A)

A B

E

Example 32: The following Venn diagram shows the sets U, A, B and C.

U
A B
C

State whether the following statements are TRUE or FALSE for the information illustrated in
the Venn diagram.

(a) A ∩ C = ∅

(b) C ∪ B = C

(c) C ⊂ (A ∪ B)

(d) A ⊂ B

(e) C  A  C

Example 33: A = {x : 6 < x  97 , x  N } is given. How many elements of the set A is divisible by 4 but not
divisible by 3?

29 091math-wb-w3-(sets)