Question

Find $A\cup B$ and $A\cap B$ when:
$A$ is the set of all prime numbers and $B$ is the set of all composite natural numbers

Answer 1

$A=\{2,3,5,7,11,......\}$

$B=\{4,6,8,9,10,12,14,.......\}$

$A\cup B=\{2,3,4,5,6,7,8,9,\mathrm{10.....}\}$

$A\cap B=\varphi$