Question

If $A\Delta B=A\cup B$, then which of the following can be correct ?

• A. $A=B$
• B. $A\cap B=\varphi$
• C. $A\Delta B=\varphi$
• D. $A\Delta B=A\sim B$

Answer 1

The correct option is B $A\cap B=\varphi$

$A\Delta B=(A-B)\cup (B-A)$

Which will be equal to $A\cup B$ only when $A\cap B=\varphi$.