Let [tex]$U=\{1,2,3, \ldots, 10\}$[/tex], [tex]$A=\{1,3,5,7\}$[/tex], [tex][tex]$B=\{1,2,3,4\}$[/tex][/tex], and [tex]$C=\{3,4,6,7,9\}$[/tex].

Select [tex]$A \cup B$[/tex] from the choices below.

A. [tex]$\{1,2,3,4,5,7\}$[/tex]
B. [tex][tex]$\{2,3,4,6,7,10\}$[/tex][/tex]
C. [tex]$\{1,3,6,7,8,10\}$[/tex]
D. [tex]$\{1,2,3,5,8,10\}$[/tex]
E. [tex][tex]$\{2,3,5,7,8,9\}$[/tex][/tex]
F. [tex]$\emptyset$[/tex]



Answer :

To find [tex]\(A \cup B\)[/tex], which is the union of the sets [tex]\(A\)[/tex] and [tex]\(B\)[/tex], we need to combine all the unique elements from sets [tex]\(A\)[/tex] and [tex]\(B\)[/tex].

Given sets:
[tex]\[ A = \{1, 3, 5, 7\} \][/tex]
[tex]\[ B = \{1, 2, 3, 4\} \][/tex]

The union of two sets [tex]\(A\)[/tex] and [tex]\(B\)[/tex] includes each element that is in either [tex]\(A\)[/tex] or [tex]\(B\)[/tex], without duplication. Therefore, we need to list all the unique elements from both sets.

Step-by-step process:
1. Start with all elements from set [tex]\(A\)[/tex]:
[tex]\[ A = \{1, 3, 5, 7\} \][/tex]

2. Add all elements from set [tex]\(B\)[/tex], but only include those that are not already in [tex]\(A\)[/tex], to avoid duplication:
[tex]\[ B = \{1, 2, 3, 4\} \][/tex]

3. Combine the elements:
[tex]\[ A \cup B = \{1, 3, 5, 7\} \cup \{1, 2, 3, 4\} \][/tex]

4. List the unique elements from both sets:
[tex]\[ A \cup B = \{1, 2, 3, 4, 5, 7\} \][/tex]

Comparing this result with the provided options:
[tex]\[ \{1,2,3,4,5,7\} \\ \{2,3,4,6,7,10\} \\ \{1,3,6,7,8,10\} \\ \{1,2,3,5,8,10\} \\ \{2,3,5,7,8,9\} \\ \emptyset \][/tex]

The correct choice that matches our result is:
[tex]\[ \{1, 2, 3, 4, 5, 7\} \][/tex]