1b. Problems: Set Operations

Question 1

A = {1,3,5,6,9}
B = {x | x is an odd int}
∈ ⋂ ⋃ ⊆ ∆ ⊖ ∉ Ø
A U B = ?

Answer 1

{x | x = 6, or x is an odd int}

an element x, where x = 6 or is an odd int

Question 2

A = {1,3,5,6,9}
B = {x | x is an odd int}
A - B = ?

Answer 2

6

what’s in A that’s NOT in B

Question 3

A = {1,3,5,6,9}
B = {x | x is an odd int}
A ⋂ B = ?

Answer 3

{1,3,5,9}

Question 4

|A| = ?

Answer 4

5

number of elements in A

Question 5

B’ = ?

Answer 5

{ x | x is an even int}

Question 6

Another way to write A - B = ?

Answer 6

~(A ⋂ B)

Question 7

A and B = finite sets

Rewrite |A U B| in terms of |A|, |B|, and |A ⋂ B|

Answer 7

|A| + |B| + |A ⋂ B|

Question 8

what must be true if |A U B| = |A| + |B| ?

Answer 8

Sets A and B have overlapping elements