在数学公式中，符号“∈”表示什么？
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Correct answer
A. 属于
Principle or equation
符号“∈”表示元素与集合之间的属于关系。
Why this answer is correct
在集合论中，a∈A 表示元素 a 属于集合 A。
Example
若 A={1,2,3}，则 2∈A 为真。
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