Show that the set of letters needed to spell $"\mathrm{CATARACT}"$ and the set of letters needed to spell $"\mathrm{TRACT}"$ are equal.
Let $X$ be the set of letters in $"CATARACT".$ Then
$X=\{ C , A , T , R \}$
Let $Y$ be the set of letters in $"TRACT".$ Then
$Y=\{T, R, A, C, T\}=\{T, R, A, C\}$
Since every element in $X$ is in $Y$ and every element in $Y$ is in $X$. It follows that $X = Y$.
State whether each of the following set is finite or infinite :
The set of letters in the English alphabet
Given the sets $A=\{1,3,5\}, B=\{2,4,6\}$ and $C=\{0,2,4,6,8\},$ which of the following may be considered as universal set $(s)$ for all the three sets $A$, $B$ and $C$
$\{ 1,2,3,4,5,6,7,8\} $
In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.
If $A \subset B$ and $B \in C,$ then $A \in C$
If $A = \{ 1,\,2,\,3,\,4,\,5\} ,$ then the number of proper subsets of $A$ is
Examine whether the following statements are true or false :
$\{a\} \subset\{a, b, c\}$