6 Let A and B be finite If A B phi then A U B A B Solutio

6. Let A and B be finite If A B = phi , then |A U B| = |A| +|B|.

Solution

As A And B Are finite sets, it means the elements of A and B are countable.

Now A intersect B = NULL ,therefore, there are no common elements between A and B.

A union B = A + B - A intersect B = A + B - 0

=> A U B = A + B