1 . 已知等差数列
满足
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71db65dd91927bf788d468bb0ed65569.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df60d284d7587442ed868985cbcde322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71db65dd91927bf788d468bb0ed65569.png)
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2 . 对于实数
,用
表示不超过
的最大整数,例如
,
,
,设x为正实数,若
为偶数,则称x为幸运数.在区间(0,1)中随机选取一个数,它是幸运数的概率为__________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dba82c9b34eaae7374d8f9bbb6abb141.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae9feb047004eb507de484a7f8c5b6a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ba98f22c3380eeb7b9323fa487c7c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17a30f271f7b5f08bd81cab2089bb4e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cfe4ffba1ab1f41d416362ee281ac10.png)
您最近一年使用:0次
2019-01-29更新
|
534次组卷
|
2卷引用:2018年全国高中数学联赛天津市预赛
2012高二·山东聊城·学业考试
3 . 已知数列
满足
.若
,则
的值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08e7dd0c91e8f471ff078569a7553040.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2fd7e75832ae791087e27dee9f4405b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5a9219209bd4544432b4ecbc97741af.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次