Find the domain and range of the relation \( R = \{ (1,2), (3,4), (5,6), (7,8) \} \).

Step 1 ：The domain of a relation \( R \) is the set of all first elements of the ordered pairs in \( R \). So, the domain of the given relation \( R \) is the set \{ 1, 3, 5, 7 \}.

Step 2 ：The range of a relation \( R \) is the set of all second elements of the ordered pairs in \( R \). So, the range of the given relation \( R \) is the set \{ 2, 4, 6, 8 \}.