If U = {1, 2, 3, 4, 5, 6} and A = {2, 3, 6}, find

Question

(a) A ∪ A'

(b) ∅ ∩ A

(c) A ∩ A'

(d) U' ∩ A

Answer 1

Assuming A' is the complement of A, which is written A^c...

 a) A∪A'=A∪{1,4,5}={1,2,3,4,5,6}=U

 b) Ø∩A=Ø because the intersection is the set of common elements but nothing in A is in the empty set which contains no elements

 c)A∩A'={2,3,6}∩{1,4,5}=Ø

 d)U'∩A=Ø because U'=Ø and now the problem is just like b)