Which interval is equal to {x ∈ ℝ : −1 < x < 3}?
Answer and explanation
Correct answer: (−1,3)
The set-builder condition −1 < x < 3 describes all real numbers strictly between −1 and 3. Because both inequalities are strict, neither boundary is included. In interval notation, an excluded endpoint is represented by a parenthesis, so the equivalent interval is (−1,3). The square-bracket alternatives incorrectly include at least one endpoint.
Frequently asked questions
What is the correct answer to this question?
(−1,3)
Why is this the correct answer?
The set-builder condition −1 < x < 3 describes all real numbers strictly between −1 and 3. Because both inequalities are strict, neither boundary is included. In interval notation, an excluded endpoint is represented by a parenthesis, so the equivalent interval is (−1,3). The square-bracket alternatives incorrectly include at least one endpoint.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Equal sets and Subsets.
