Solved Examples on Set Theory
Example 1: If A and B are two sets such that n(A) = 17, n(B) = 23 and n(A ∪ B) = 38 then find n(A ∩ B).
Solution:
We know that n(A ∪ B) = n(A) + n(B) – n(A ∩ B)
⇒ 38 = 17 + 23 – n(A ∩ B)
⇒ n(A ∩ B) = 40 – 38 = 2
Example 2: If X = {1, 2, 3, 4, 5}, Y = {4, 5, 6, 7, 8}, and Z = {7, 8, 9, 10, 11}, find (X ∪ Y), (X ∪ Z), (Y ∪ Z), (X ∪ Y ∪ Z), and X ∩ (Y ∪ Z)
Solution:
(X ∪ Y) = {1, 2, 3, 4, 5} ∪ {4, 5, 6, 7, 8} = {1, 2, 3, 4, 5, 6, 7, 8}
(X ∪ Z) = {1, 2, 3, 4, 5} ∪ {7, 8, 9, 10, 11} = {1, 2, 3, 4, 5, 7, 8, 9, 10, 11}
(Y ∪ Z) = {4, 5, 6, 7, 8} ∪ {7, 8, 9, 10, 11} = {4, 5, 6, 7, 8, 9, 10, 11}
(X ∪ Y ∪ Z) = {1, 2, 3, 4, 5} ∪ {4, 5, 6, 7, 8} ∪ {7, 8, 9, 10, 11} = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}
X ∩ (Y ∪ Z) = {1, 2, 3, 4, 5} ∩ {4, 5, 6, 7, 8, 9, 10, 11} = {4, 5}
What is Set Theory? Definition, Types, Operations
Set Theory is a branch of logical mathematics that studies the collection of objects and operations based on it. A set is simply a collection of objects or a group of objects. For example, a group of players in a football team is a set and the players in the team are its objects.
The words collection, aggregate, and class are synonymous with set. On the other hand elements, members, and objects are synonymous and stand for the members of the set of which the set is comprised.
In this article, we will learn about the set theory and cover sets in detail. Look at the content guide that shows all the topics, we will be covering in this article.
Table of Content
- Set Theory Definition
- History of Set Theory
- Examples of Sets
- Important Terms Related to Set Theory
- Elements of a Set
- Cardinal Number of a Set
- Representation of Sets
- Roster Form
- Set Builder Form
- Types of Sets
- Set Theory Symbols
- Set Theory Operations
- Properties of Set Operations
- Set Theory Formulas
- De Morgan’s Laws
- De Morgan’s Law of Union
- De Morgan’s Law of Intersection
- Visual Representation of Sets Using Venn Diagram
- Solved Examples on Set Theory
- Practice Problems on Set Theory