Question

If a and b are disjoint sets then what is a intersection b

Answer 1

If A and B are disjointed sets, how can you find n (A union B)?

Answer

3

Follow

Request

More

4 ANSWERS



Daity Bhattacharjee, Statistics hons.(B.Sc) Vivekananda College, Thakurpukur, BIDYA BHARATI GIRLS' HIGH SCHOOL

Answered Aug 28, 2017

Two sets are said to be disjoint if they have no element in common. Equivalently, disjoint sets are sets whose intersection is the empty set. For example, {1, 2, 3} and {4, 5, 6} are disjoint sets,( as they have no element in common) while {1, 2, 3} and {3, 4, 5} are not.(as the element 3 is in common).

The union of two sets A and B is the set of elements which are in A, in B, or in both A and B. In figures;



First consider the case where the sets A and B are disjoint.

In that case,

The number of elements in the union (A∪B) is simply the sum of the number of elements in A and the number of elements in B: |A ∪ B| = |A| + |B|. [ |A|→no of elements in A and other notations mean similar].

But if A and B overlap, then the latter formula does not hold because, we are counting the elements in the intersection (A ∩ B) twice. Compensating for that leads to the given formula: |A ∪ B| = |A| + |B| − |A ∩ B|.

[ Note : n(A U B) is also denoted as |A U B| ]



Elements in (AUB)=elements in (A)+ elements in (B).

In above example, union of disjoint sets is;

Element set in A + Element set in B

={1,2,3,5,7,9}

Answer 2

Answer:

Here is your answer

Step-by-step explanation:

The number of elements in the union (A∪B) is simply the sum of the number of elements in A and the number of elements in B: |A ∪ B| = |A| + |B|. [ |A|→no of elements in A and other notations mean similar].

But if A and B overlap, then the latter formula does not hold because, we are counting the elements in the intersection (A ∩ B) twice. Compensating for that leads to the given formula: |A ∪ B| = |A| + |B| − |A ∩ B|.

[ Note : n(A U B) is also denoted as |A U B| ]

Elements in (AUB)=elements in (A)+ elements in (B).

In above example, union of disjoint sets is;

Element set in A + Element set in B

={1,2,3,5,7,9}