Question

If A and B are two sets such that $AsubsetB,$ then find :

(i) $A\cap B$ (ii) $A\cup B$

Answer 1

(i) $A\cap B$ denotes intersection of the two sets A and B, which consists of elements which are common to both A and B.

Since $A\subset B$ , every element of A is already an element of B.

$\therefore A\cap B=A$

(ii) $A\cup B$ denotes the union of the sets A and B which consits of elements which are either in A or B or in both A and B.

Since $A\subset B$ , every element of A is already an element of B.

$\therefore A\cup B=B$