Question:
Let A = {2, 4, 5, 7} and b = {1, 2, 3, 4, 5, 6, 7, 8}.
Let $R=\{(x, y) x \in A, y \in B$ and $x$ divides $y\} .$
(i) Write R in roster form.
(ii) Find dom (R) and range (R).
Solution:
Given: A = {2, 4, 5, 7} and b = {1, 2, 3, 4, 5, 6, 7, 8}
(i) $R=\{(x, y) x \in A, y \in B$ and $x$ divides $y\}$
So, R in Roster Form,
$\mathrm{R}=\{(2,2),(2,4),(2,6),(2,8),(4,4),(4,8),(5,5),(7,7)\}$
(ii) $\operatorname{Dom}(R)=\{2,4,5,7\}$
Range $(R)=\{2,4,5,7,6,7,8\}$