Show that $A \cup B=A \cap B$ implies $A=B$.
Let $a \in A.$ Then $a \in A \cup$ $B$. Since $A \cup B=A \cap B, a \in A \cap B$.
So $a \in B$
Therefore, $A \subset$ $B.$ Similarly, if $b \in B$, then $b \in A \cup$ $B.$
Since $A \cup B=A \cap B, b \in A \cap B .$ So, $b \in A .$
Therefore, $B \subset A .$ Thus, $A=B$
Let $A = \{a, b, c\}, B = \{b, c, d\}, C = \{a, b, d, e\},$ then $A \cap (B \cup C)$ is
If $S$ and $T$ are two sets such that $S$ has $21$ elements, $T$ has $32$ elements, and $S$ $\cap \,T$ has $11$ elements, how many elements does $S\, \cup$ $T$ have?
Consider the sets $X$ and $Y$ of $X = \{ $ Ram , Geeta, Akbar $\} $ and $Y = \{ $ Geeta, David, Ashok $\} $ Find $X \cap Y$
If $A = \{ x:x$ is a natural number $\} ,B = \{ x:x$ is an even natural number $\} $ $C = \{ x:x$ is an odd natural number $\} $ and $D = \{ x:x$ is a prime number $\} ,$ find
$A \cap B$
The shaded region in given figure is-