已知数列 1,3,5,⋯,2n−1,⋯, 则 21 是这个数列的_刷题宝

题干

已知数列 1,3,5,⋯,2n−1,⋯, 则 21 是这个数列的（）

A：第10项

B：第11项

C：第12项

D：第21项

上一题下一题 0.0难度选择题更新时间:2012-04-17 05:27:11

答案(点此获取答案解析）

B

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