List all the elements of the following sers :
$C = \{ x:x$ is an integer ${\rm{; }}{x^2} \le 4\} $
$C = \{ x:x{\rm{ }}$ is an integer ${\rm{ }};{x^2} \le 4\} $
It can be seen that
${( - 1)^2} = 1\, \le \,4;{( - 2)^2} = 4\, \le \,4;{( - 3)^2} = 9\, > \,4$
$0^{2}=0 \leq 4$
$1^{2}=1 \leq 4$
$2^{2}=4 \leq 4$
$3^{2}=9>4$
$\therefore C=\{-2,-1,0,1,2\}$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{ 3,4\} \subset A$
Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:
$ 0\, ........\, A $
Write the following sets in roster form :
$D = \{ x:x$ is a prime number which is divisor of $60\} $
Which of the following are sets ? Justify your answer.
The collection of all the months of a year beginning with the letter $\mathrm{J}.$
Which of the following are examples of the null set
$\{ x:x$ is a natural numbers, $x\, < \,5$ and $x\, > \,7\} $