If U = ℝ, A = (-2, 6], and B = [0, 9), what is A' ∪ B'?
Answer and explanation
Correct answer: (-∞, 0) ∪ (6, ∞)
Using De Morgan's law, A' ∪ B' = (A ∩ B)'. The intersection of A = (-2, 6] and B = [0, 9) is [0, 6]. Taking its complement in ℝ excludes every number from 0 through 6, including both endpoints. Therefore the result is (-∞, 0) ∪ (6, ∞). The open endpoints are essential.
Frequently asked questions
What is the correct answer to this question?
(-∞, 0) ∪ (6, ∞)
Why is this the correct answer?
Using De Morgan's law, A' ∪ B' = (A ∩ B)'. The intersection of A = (-2, 6] and B = [0, 9) is [0, 6]. Taking its complement in ℝ excludes every number from 0 through 6, including both endpoints. Therefore the result is (-∞, 0) ∪ (6, ∞). The open endpoints are essential.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Complement of a Set and Its Properties.