Difficulty: Medium
Correct Answer: 0 ⊂ A
Explanation:
Introduction / Context:
The stem uses “0” where standard notation would use ϕ (empty set). Applying Recovery-First, interpret “0 ⊂ A” as “ϕ ⊂ A”. We analyze membership values of A and the truth of each statement under that repair.
Given Data / Assumptions:
Concept / Approach:
Check each option against A’s generated values, and fix the nonstandard symbol “0” to ϕ when it denotes the empty set in subset relations.
Step-by-Step Solution:
n=1 gives 0, so 0 ∈ A is true as a number, but the stem’s choices mix numeric 0 with set symbols; interpret carefully.1/3 ∈ A since (2−1)/(2+1) = 1/3 → so “1/3 ∉ A” is false.ϕ ⊂ A is always true for any set A (empty set is a subset of every set).
Verification / Alternative check:
A contains many fractions in (−1, 1). Regardless of exact contents, ϕ ⊂ A remains universally true; thus the corrected reading of option “0 ⊂ A” becomes the valid statement.
Why Other Options Are Wrong:
“0 ⊃ A” is ill-formed; “1/3 ∉ A” is false; “A = ϕ” is false since A is nonempty; “0 ∈ A” mixes numeral vs. set-symbol usage and is ambiguous in the given list.
Common Pitfalls:
Confusing numeral 0 with the empty set ϕ; always distinguish element membership from subset relations.
Final Answer:
0 ⊂ A
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