Write the following sets in roster form :
$\mathrm{E} =$ The set of all letters in the world $\mathrm{TRIGONOMETRY}$
$E =$ The set of all letters in the word $TRIGONOMETRY$
There are $12$ letters in the word $TRIGONOMETRY,$ out of which letters $T,$ $R$ and $O$ are repeated
Therefore, this set can be written in roster form as
$E =\{ T , R , I , G , O , N , M , E , Y \}$
Which of the following are sets ? Justify your answer.
The collection of all boys in your class.
List all the elements of the following sers :
$F = \{ x:x$ is a consonant in the Englishalphabet which precedes $k\} $
How many elements has $P(A),$ if $A=\varnothing ?$
Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:
$ 4\, ......... \, A $
Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?