Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:

$ 0\, ……..\, A $

State whether each of the following set is finite or infinite :

The set of lines which are parallel to the $x\,-$ axis

Examine whether the following statements are true or false :

$\{a\} \subset\{a, b, c\}$

List all the elements of the following sers :

$B = \{ x:x$ is an integer $; – \frac{1}{2} < n < \frac{9}{2}\} $

Let $A=\{a, e, i, o, u\}$ and $B=\{a, i, u\} .$ Show that $A \cup B=A$