Question

explain both terms step by step

Answer 1

Question 5

We know that by default that,

n(AuB)=n(A)+ n(B)-n(AnB)

here we are taking two sets A and B (Area of A and B)

but no area is repeating.

So if we take three sets A B AND C, then we are taking area of A,B AND C

they all are intersecting to each other so that area we are interested in taking is larger than the actual one. so that we will subtract area of intersection one time from the equation,

A+B+C-(A intersection B)-(A intersection C)-(B intersection C)

intersection =n

and when will do this so that area of (Aintersection B intersectionC)

will be removed too ,therefore we will add (A intersection B intersection C) in equation.

Question 6

It means that if A,B , C  are any three sets (finite sets)  then number of elements in two sets would be ,

n(A intersection B) + n(B intersection C) + n(C  intersection A) – 3n(A intersection B intersection C)