Show that the set of letters needed to spell $"\mathrm{CATARACT}"$ and the set of letters needed to spell $"\mathrm{TRACT}"$ are equal.
Write the following sets in roster form :
$\mathrm{E} =$ The set of all letters in the world $\mathrm{TRIGONOMETRY}$
Write the following sets in the set-builder form :
${\rm{\{ 2,4,8,16,32\} }}$
Let $A, B,$ and $C$ be the sets such that $A \cup B=A \cup C$ and $A \cap B=A \cap C$. Show that $B = C$
Which of the following sets are finite or infinite.
$\{1,2,3 \ldots .\}$