If J₁ = {x : x ∈ ℤ, |x| < 3}, how many elements does J₁ have?
Answer and explanation
Correct answer: 5
For an integer x, the inequality |x| < 3 is equivalent to -3 < x < 3. The integers strictly between -3 and 3 are -2, -1, 0, 1, and 2. Thus J₁ = {-2, -1, 0, 1, 2}, which contains five distinct elements. The endpoints -3 and 3 are excluded because the inequality is strict, so the correct answer is 5.
Frequently asked questions
What is the correct answer to this question?
5
Why is this the correct answer?
For an integer x, the inequality |x| < 3 is equivalent to -3 < x < 3. The integers strictly between -3 and 3 are -2, -1, 0, 1, and 2. Thus J₁ = {-2, -1, 0, 1, 2}, which contains five distinct elements. The endpoints -3 and 3 are excluded because the inequality is strict, so the correct answer is 5.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.