The problem consists of several parts related to set theory: listing elements of sets, finding set operations, simplifying set expressions using laws, describing sets in set-builder notation, proving set laws, representing sets using Venn diagrams, and proving a set identity. We will address questions 1, 2, 3 and 4 in this response.
Discrete MathematicsSet TheorySet OperationsSet NotationDe Morgan's LawIntersectionUnionSet Difference
2025/4/15
1. Problem Description
The problem consists of several parts related to set theory: listing elements of sets, finding set operations, simplifying set expressions using laws, describing sets in set-builder notation, proving set laws, representing sets using Venn diagrams, and proving a set identity. We will address questions 1, 2, 3 and 4 in this response.
2. Solution Steps
1(a) List the elements of the set {x: x is an integer greater than -2 but less than 9}.
The integers greater than -2 are -1, 0, 1, 2, ...
The integers less than 9 are 8, 7, 6, 5, ...
Therefore, the set is {-1, 0, 1, 2, 3, 4, 5, 6, 7, 8}.
1(b) List the elements of the set {x: x is an integer} ∩ {0, √3, π, 2i }.
The set {x: x is an integer} consists of integers.
The set {0, √3, π, 2i } consists of 0, the square root of 3, pi, and 2 times the imaginary unit i.
The intersection of these two sets consists of elements that are both integers and are in {0, √3, π, 2i }.
The only integer in {0, √3, π, 2i } is
0. Therefore, the intersection is {0}.
1(c) List the elements of the set {x² + 1: x ∈ A} where A = {-2, -1, 0, 1, 2}.
We calculate for each element in :
If , then .
If , then .
If , then .
If , then .
If , then .
The set is {5, 2, 1, 2, 5} = {1, 2, 5}.
1(d) List the elements of the set { √x + 2 : x ∈ B} where B = {-3, -4, 0, 1, 2}.
We calculate for each element in :
If , then , which is not a real number.
If , then , which is not a real number.
If , then .
If , then .
If , then .
Assuming we are looking for real numbers, the set is {√2, √3, 2}.
2. Given A = {0, 2, 4, 6, 8, 10}, B = {1, 3, 5, 7, 9}, C = {1, 2, 4, 5, 7, 8}, D = {1, 2, 3, 5, 7, 8, 9}.
(a) (A - B) - C
.
(b) (A ∩ B) U (A ∩ C)
(empty set, since there are no common elements)
.
(c) D ∩ (A ∩ C)
.
(e) (A U B) - (C ∩ D)
.
3. Using the laws of sets, simplify the following
(a)
Using De Morgan's law:
(using De Morgan's law again)
(b) (A - B) U (A ∩ B)
, where is the universal set.
(c) (A - B)'
(using De Morgan's Law)
(d) (A U B) ∩ (A U B')
4. Describe each of the following in set builder notation:
(a) A = {1, 8, 27, 64, 125}
A = {}
(b) B = {0, 2, 4, 6, 8, 12}
B = {}
(c) C = {1, 3, 9, 27, 81}
C = {}
(d) D = {(1,2), (2,4), (3,6), (4,8)}
D = {}
3. Final Answer
1(a) {-1, 0, 1, 2, 3, 4, 5, 6, 7, 8}
1(b) {0}
1(c) {1, 2, 5}
1(d) {√2, √3, 2}
2(a) {0, 6, 10}
2(b) {2, 4, 8}
2(c) {2, 8}
2(e) {0, 3, 6, 9, 10}
3(a)
3(b) A
3(c) A' U B
3(d) A
4(a) {}
4(b) {}
4(c) {}
4(d) {}