What is the roster form of J = {x : x = 2n + 1, n ∈ ℕ, n < 5}?
Advertisement
Answer and explanation
Correct answer: J = {3, 5, 7, 9}
For n ∈ ℕ, taking the usual school convention ℕ = {1, 2, 3, ...}, the condition n < 5 gives n = 1, 2, 3, 4. Substituting these values in x = 2n + 1 gives 3, 5, 7, and 9. Therefore, the roster form is J = {3, 5, 7, 9}. The value n = 5 is excluded because the inequality is strict.
Frequently asked questions
What is the correct answer to this question?
J = {3, 5, 7, 9}
Why is this the correct answer?
For n ∈ ℕ, taking the usual school convention ℕ = {1, 2, 3, ...}, the condition n < 5 gives n = 1, 2, 3, 4. Substituting these values in x = 2n + 1 gives 3, 5, 7, and 9. Therefore, the roster form is J = {3, 5, 7, 9}. The value n = 5 is excluded because the inequality is strict.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
Advertisement