Which of the following are sets ? Justify your answer.
A team of eleven best-cricket batsmen of the world.
A team of eleven best cricket batsmen of the world is not a well-defined collection because the criteria for determining a batsman's talent may vary from person to person.
Hence, this collection is not a set.
Write the following as intervals :
$\{ x:x \in R, - 12\, < \,x\, < \, - 10\} $
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 boys in your class.
Write the following sets in the set-builder form :
$\{ 1,4,9 \ldots 100\} $
Write the following intervals in set-builder form :
$\left( {6,12} \right]$