If the universal set is U = ℝ and A = {x ∈ ℝ : x < −4 or x ≥ 2}, what is A′?
Answer and explanation
Correct answer: [−4, 2)
The set A contains all real numbers less than −4 together with all real numbers greater than or equal to 2. Its complement therefore contains the numbers that are not less than −4 and are also less than 2. Thus −4 is included, while 2 is excluded. Consequently, A′ = [−4, 2), so option A is correct.
Frequently asked questions
What is the correct answer to this question?
[−4, 2)
Why is this the correct answer?
The set A contains all real numbers less than −4 together with all real numbers greater than or equal to 2. Its complement therefore contains the numbers that are not less than −4 and are also less than 2. Thus −4 is included, while 2 is excluded. Consequently, A′ = [−4, 2), so option A is correct.
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.