Question

Let $A=\{1,2,3,4,6\}$ and $R$ be the relation on $A$ defined by $\left\{\right(a,b):a,b\in A,b$ is exactly divisible by $a\}$
(i) Write $R$ in roster form
(ii) Find the domain of $R$
(iii) Find the range of $R$

Answer 1

$A=\{1,2,3,4,6\}$

$R=\left\{\right(a,b):a,b\in A,b\text{is exactly divisible by}a\}$
(i) $R=\left\{\right(1,1),(1,2),(1,3),(1,4),(1,6),(2,2),(2,4),(2,6),(3,3),(3,6),(4,4),(6,6\left)\right\}$
(ii) Domain of $R=\{1,2,3,4,6\}$
(iii) Range of $R=\{1,2,3,4,6\}$