Question: Let $A=\{2,3,4,5\}$ and $B=\{1,3,4\}$. If $R$ is the relation from $A$ to $B$ given by a $R b$ if "a is a divisor of $b$ ". Write $R$ as a set of ordered pairs.
Solution:
Since $R=\{(a, b): a, b \in N: a$ is a divisor of $b\}$
So, $R=\{(2,4),(3,3),(4,4)\}$
