Let [tex]\( S \)[/tex] be the universal set, where:
[tex]\[ S = \{1, 2, 3, \ldots, 13, 14, 15\} \][/tex]

Let sets [tex]\( A \)[/tex], [tex]\( B \)[/tex], and [tex]\( C \)[/tex] be subsets of [tex]\( S \)[/tex], where:
[tex]\[
\begin{array}{l}
\text{Set } A = \{1, 2, 5, 6, 7, 10, 12, 15\} \\
\text{Set } B = \{1, 2, 3, 8, 11, 13, 14\} \\
\text{Set } C = \{1, 4, 7, 9, 12, 15\}
\end{array}
\][/tex]

Find the following:

a) List the elements in the set [tex]\( A \cup B \)[/tex]:
[tex]\[ A \cup B = \{ \square \} \][/tex]
Enter the elements as a list, separated by commas. If the result is the empty set, enter DNE.

b) List the elements in the set [tex]\( B \cap C \)[/tex]:
[tex]\[ B \cap C = \{ \square \} \][/tex]
Enter the elements as a list, separated by commas. If the result is the empty set, enter DNE.

c) List the elements in the set [tex]\( B^C \)[/tex]:
[tex]\[ B^C = \{ \square \} \][/tex]
Enter the elements as a list, separated by commas. If the result is the empty set, enter DNE. You may want to draw a Venn Diagram to help answer this question.



Answer :

To solve the problem, we need to find [tex]\( A \cup B \)[/tex], [tex]\( B \cap C \)[/tex], and [tex]\( B^C \)[/tex] given the sets [tex]\( S \)[/tex], [tex]\( A \)[/tex], [tex]\( B \)[/tex], and [tex]\( C \)[/tex].

### Step-by-Step Solution:

1. List the elements in the set [tex]\( A \cup B \)[/tex]:

The union of two sets, [tex]\( A \cup B \)[/tex], contains all elements that are in either set [tex]\( A \)[/tex] or set [tex]\( B \)[/tex] or in both.

Given:
[tex]\[ A = \{1, 2, 5, 6, 7, 10, 12, 15\} \][/tex]
[tex]\[ B = \{1, 2, 3, 8, 11, 13, 14\} \][/tex]

Merging all elements from both sets without duplicates:
[tex]\[ A \cup B = \{1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15\} \][/tex]

2. List the elements in the set [tex]\( B \cap C \)[/tex]:

The intersection of two sets, [tex]\( B \cap C \)[/tex], contains only the elements that are present in both set [tex]\( B \)[/tex] and set [tex]\( C \)[/tex].

Given:
[tex]\[ B = \{1, 2, 3, 8, 11, 13, 14\} \][/tex]
[tex]\[ C = \{1, 4, 7, 9, 12, 15\} \][/tex]

Identify the common elements:
[tex]\[ B \cap C = \{1\} \][/tex]

3. List the elements in the set [tex]\( B^C \)[/tex]:

The complement of a set [tex]\( B \)[/tex] with respect to the universal set [tex]\( S \)[/tex], denoted as [tex]\( B^C \)[/tex] or [tex]\( \bar{B} \)[/tex], contains all elements that are in [tex]\( S \)[/tex] but not in [tex]\( B \)[/tex].

Given:
[tex]\[ S = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15\} \][/tex]
[tex]\[ B = \{1, 2, 3, 8, 11, 13, 14\} \][/tex]

Subtract the elements of B from S:
[tex]\[ B^C = \{4, 5, 6, 7, 9, 10, 12, 15\} \][/tex]

### Final Results:

a) [tex]\( A \cup B = \{1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15\} \)[/tex]

b) [tex]\( B \cap C = \{1\} \)[/tex]

c) [tex]\( B^C = \{4, 5, 6, 7, 9, 10, 12, 15\} \)[/tex]