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1 . 如图所示,九连环是中国的一种古老的智力游戏,它环环相扣,趣味无穷.它主要由九个圆环及框架组成,每个圆环都连有一个直杆,各直杆在后一个圆环内穿过,九个直杆的另一端用平板或者圆环相对固定,圆环在框架上可以解下或者套上.九连环游戏按某种规则将九个环全部从框架上解下或者全部套上.将第
个圆环解下最少需要移动的次数记为
(
且
),已知
,
,且通过该规则可得
,则解下第5个圆环最少需要移动的次数为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/53e47107-09d9-478d-a825-fbfbaef64c9b.png?resizew=222)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38fcec7af3520884b173b29bda6c657a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6842fb24ab3b2235b66ca392ebcbc0be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/249a976e88133f3b3733f09137cf5c42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9da4fdfdddc259dcef9fdd4b826b64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e2a636c93bcb2dc6e80f43e48dff3fb.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/53e47107-09d9-478d-a825-fbfbaef64c9b.png?resizew=222)
A.7 | B.16 | C.19 | D.21 |
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2020-01-07更新
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668次组卷
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5卷引用:青海省西宁市2020届高三复习检测(二)数学试题