What is the interval form of the set {x ∈ R : x ≥ 3}?
Answer and explanation
Correct answer: [3, ∞)
The condition x ≥ 3 includes 3 because the inequality contains the equality sign. It also includes every real number greater than 3, continuing without an upper bound. Thus the interval begins with a square bracket at 3 and extends toward infinity: [3, ∞). Infinity is never an endpoint that can be reached, so a round bracket is always used beside ∞. Therefore option B is correct.
Frequently asked questions
What is the correct answer to this question?
[3, ∞)
Why is this the correct answer?
The condition x ≥ 3 includes 3 because the inequality contains the equality sign. It also includes every real number greater than 3, continuing without an upper bound. Thus the interval begins with a square bracket at 3 and extends toward infinity: [3, ∞). Infinity is never an endpoint that can be reached, so a round bracket is always used beside ∞. Therefore option B is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
