Using properties of sets, show that (i) A∪(A∩B)=A (ii) A∩(A∪B)=A
Solution:
(i) To show: A∪(A∩B)=A We know that A⊆A ⇒ A∩B⊆A ⇒ A∪(A∩B)⊆A. (1) Also, A⊆A∪(A∩B) (2) From (1) and (2), A∪(A∩B)=A (ii) To show: A∩(A∪B)=A A∩(A∪B)=(A∩A)∪(A∩B)=A∪(A∩B)=A (by (i)) ⇒A∩(A∪B)=A