Question:
Let A = {2, 3, 4, 5} and B = {3, 6, 7, 10}.
Let $R=\{(x, y): x \in A, y \in B$ and $x$ is relatively prime to $y\} .$
(i) Write $\mathbf{R}$ in roster form.
(ii) Find dom (R) and range (R).
Solution:
Given: A = {2, 3, 4, 5} and B = {3, 6, 7, 10}
(i) $R=\{(x, y),: x \in A, y \in B$ and $x$ is relatively prime to $y\}$
So, R in Roster Form,
R = {(2, 3), (2, 7), (3, 7), (3, 10), (4, 3), (4, 7), (5, 3), (5, 6), (5, 7)}
(ii) $\operatorname{Dom}(\mathrm{R})=\{2,3,4,5\}$
Range(R) = {3, 6, 7, 10}