Universal Set and Given Sets

Oct 13, 2025 by wbrum.org 141 views

Introduction

In set theory, the union and intersection of sets are fundamental operations used to combine and manipulate sets. The union of two sets is the set of all elements that are in either of the sets, while the intersection of two sets is the set of all elements that are common to both sets. In this article, we will explore the concept of finding the union of the intersection of two sets, given the universal set U and the sets A, B, and C.

Universal Set and Given Sets

The universal set U is defined as the set of all integers from 1 to 8, inclusive. The sets A, B, and C are defined as follows:

U = {1, 2, 3, ..., 8}
A = {1, 2, 3, 4}
B = {1, 2, 3}
C = {2, 3, 5, 6, 7}

Understanding Set Operations

Before we proceed to find the union of the intersection of sets A, B, and C, let's review the definitions of union and intersection.

Union: The union of two sets A and B, denoted by A ∪ B, is the set of all elements that are in A, in B, or in both A and B.
Intersection: The intersection of two sets A and B, denoted by A ∩ B, is the set of all elements that are common to both A and B.

Finding the Intersection of Sets B and C

To find the union of the intersection of sets A, B, and C, we first need to find the intersection of sets B and C.

B ∩ C = {2, 3}

The intersection of sets B and C is the set of all elements that are common to both B and C, which are 2 and 3.

Finding the Union of the Intersection of Sets A, B, and C

Now that we have found the intersection of sets B and C, we can proceed to find the union of the intersection of sets A, B, and C.

A ∪ (B ∩ C) = A ∪ {2, 3}

To find the union of sets A and {2, 3}, we need to combine all elements that are in A, in {2, 3}, or in both A and {2, 3}.

A ∪ {2, 3} = {1, 2, 3, 4}

The union of sets A and {2, 3} is the set of all elements that are in A, in {2, 3}, or in both A and {2, 3}, which are 1, 2, 3, and 4.

Conclusion

In conclusion, the union of the intersection of sets A, B, and C is the set of all elements that are in A, in the intersection of B and C, or in both A and the intersection of B and C. By applying the definitions of union and intersection, we have found that the union of the intersection of sets A, B, and C is {1, 2, 3, 4}.

Final Answer

Introduction

In our previous article, we explored the concept of finding the union of the intersection of two sets, given the universal set U and the sets A, B, and C. In this article, we will answer some frequently asked questions related to set operations and provide additional examples to help solidify your understanding of these concepts.

Q&A

Q: What is the difference between the union and intersection of sets?

A: The union of two sets A and B, denoted by A ∪ B, is the set of all elements that are in A, in B, or in both A and B. The intersection of two sets A and B, denoted by A ∩ B, is the set of all elements that are common to both A and B.

Q: How do I find the union of two sets?

A: To find the union of two sets A and B, you need to combine all elements that are in A, in B, or in both A and B. For example, if A = {1, 2, 3} and B = {3, 4, 5}, then A ∪ B = {1, 2, 3, 4, 5}.

Q: How do I find the intersection of two sets?

A: To find the intersection of two sets A and B, you need to identify all elements that are common to both A and B. For example, if A = {1, 2, 3} and B = {3, 4, 5}, then A ∩ B = {3}.

Q: What is the universal set?

A: The universal set, denoted by U, is the set of all elements that are being considered in a particular problem or context. For example, if we are working with the set of all integers from 1 to 10, then U = {1, 2, 3, ..., 10}.

Q: How do I find the union of the intersection of two sets?

A: To find the union of the intersection of two sets A and B, you need to first find the intersection of A and B, and then find the union of the result with set A. For example, if A = {1, 2, 3} and B = {3, 4, 5}, then A ∪ (A ∩ B) = A ∪ {3} = {1, 2, 3}.

Q: What is the difference between the symmetric difference and the union of the intersection of two sets?

A: The symmetric difference of two sets A and B, denoted by A Δ B, is the set of all elements that are in A or in B, but not in both. The union of the intersection of two sets A and B, denoted by A ∪ (A ∩ B), is the set of all elements that are in A, in the intersection of A and B, or in both A and the intersection of A and B.

Q: How do I find the symmetric difference of two sets?

A: To find the symmetric difference of two sets A and B, you need to identify all elements that are in A or in B, but not in both. For example, if A = {1, 2, 3} and B = {3, 4, 5}, then A Δ B = {1, 2, 4, 5}.

Examples

Example 1: Finding the Union of the Intersection of Sets A and B

Let A = {1, 2, 3} and B = {3, 4, 5}. Find the union of the intersection of sets A and B.

A ∪ (A ∩ B) = A ∪ {3} = {1, 2, 3}

Example 2: Finding the Symmetric Difference of Sets A and B

Let A = {1, 2, 3} and B = {3, 4, 5}. Find the symmetric difference of sets A and B.

A Δ B = {1, 2, 4, 5}

Conclusion

In conclusion, set operations are an essential part of mathematics and are used to combine and manipulate sets. The union and intersection of sets are fundamental operations used to find the common elements and unique elements of two sets. By understanding these concepts and practicing with examples, you can become proficient in set operations and apply them to solve problems in mathematics and other fields.

Final Answer

The final answer is {1, 2, 3, 4}.