Question:
If P = {x : x < 3, x ∈ N}, Q = {x : x ≤ 2, x ∈ W}. Find (P ∪ Q) × (P ∩ Q), where W is the set of whole numbers.
Solution:
According to the question,
P = {x: x < 3, x ∈N}, Q = {x : x ≤ 2, x ∈W} where W is the set of whole numbers
P = {1, 2}
Q = {0, 1, 2}
Now
(P∪Q) = {1, 2}∪{0, 1, 2} = {0, 1, 2}
And,
(P∩Q) = {1, 2}∩{0, 1, 2} = {1, 2}
We need to find the Cartesian product of (P∪Q) = {0, 1, 2} and (P∩Q) = {1, 2}
So,
(P∪Q) × (P∩Q) = {0, 1, 2} × {1, 2}
= {(0, 1), (0, 2), (1, 1), (1, 2), (2, 1), (2, 2)}
Hence, the Cartesian product = {(0, 1), (0, 2), (1, 1), (1, 2), (2, 1), (2, 2)}