In rule method the null set is represented by
$\{\}$
$\phi $
$\{ x:x = x\} $
$\{ x:x \ne x\} $
The number of non-empty subsets of the set $\{1, 2, 3, 4\}$ is
Which of the following sets are finite or infinite.
The set of positive integers greater than $100$
If $Q = \left\{ {x:x = {1 \over y},\,{\rm{where \,\,}}y \in N} \right\}$, then
The number of elements in the set $\{ (a,\,b):2{a^2} + 3{b^2} = 35,\;a,\,b \in Z\} $, where $Z$ is the set of all integers, is
Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:
$ 2 \, ....... \, A $