Q. 2 E5.0( 2 Votes )

# Let A = {1, 2, 4, 5} B = {2, 3, 5, 6} C = {4, 5, 6, 7}. Verify the following identities:

A– (B ∩ C) = (A – B) ∪ (A – C)

Answer :

(B ∩ C) = {x:x ϵ B and x ϵ C}

= {5, 6}

(A – (B ∩ C)) =

A–(B ∩ C) is defined as {x ϵ A : x ∉(B ∩ C)}

A = {1, 2, 4, 5}

(B ∩ C) = {5, 6}

(A – (B ∩ C)) = {1, 2, 4}

R.H.S:

(A – B) =

A–B is defined as {x ϵ A : x ∉ B}

A = {1, 2, 4, 5}

B = {2, 3, 5, 6}

A–B = {1, 4}

(A–C) =

A–C is defined as {x ϵ A : x ∉ C}

A = {1, 2, 4, 5}

C = {4, 5, 6, 7}

A–C = {1, 2}

(A – B) ∪ (A–C) = {x:x ϵ (A – B) OR x ϵ (A – C) }.

= {1, 2, 4}

Hence verified.

Rate this question :

Let A = {a, b, c, d}, B = {c, d, e} and C = {d, e, f, g}. Then verify each of the following identities:

(i) A × (B ∩ C) = (A × B) ∩ (A × C)

(ii) A × (B – C) = (A × B) – (A × C)

(iii) (A × B) ∩ (B × A) = (A ∩ B) × (A ∩ B)

RS Aggarwal - Mathematics

If A and B be two sets such that n(A) = 3, n(B) = 4 and n(A ∩ B) = 2 then find.

(i) n(A × B)

(ii) n(B × A)

(iii) n(A × B) ∩ (B × A)

RS Aggarwal - Mathematics

(i) If A ⊆ B, prove that A × C ⊆ B × C for any set C.

(ii) If A ⊆ B and C ⊆ D then prove that A × C ⊆ B × D.

RS Aggarwal - Mathematics

Using properties of sets prove the statements given

For all sets A and B, (A ∪ B) – B = A – B

Mathematics - ExemplarIf A and B are two sets such that n(A) = 23, n(b) = 37 and n(A – B) = 8 then find n(A ∪ B).

Hint n(A) = n(A – B) + n(A ∩ B) n(A ∩ B) = (23 – 8) = 15.

RS Aggarwal - Mathematics

If A and B are two sets such than n(A) = 54, n(B) = 39 and n(B – A) = 13 then find n(A ∪ B).

Hint n(B) = n(B – A) + n(A ∩ B) ⇒ n(A ∩ B) = (39 – 13) = 26.

RS Aggarwal - Mathematics

If n(A) = 3 and n(B) = 5, find:

(i) The maximum number of elements in A ∪ B,

(ii) The minimum number of elements in A ∪ B.

RS Aggarwal - Mathematics

For any sets A, B and C prove that:

A × (B – C) = (A × B) – (A × C)

RS Aggarwal - Mathematics