1 . 已知正项数列
的首项
,前
项和
满足
.
(Ⅰ)求证:
为等差数列,并求数列
的通项公式;
(Ⅱ)记数列
的前
项和为
,若对任意的
,不等式
恒成立,求实数
的取值范围.
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/68e7a68728494e21a277d119bdbb4d75.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/68d47144532246e080daa5a34cedf512.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/ee210b0a185f4b8eae2ab4ec19921647.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/5206cc9b414b40afaee99912e52f262e.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/df1adfeb14284cc8bb63c46d95beb890.png)
(Ⅰ)求证:
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/37512d7dbfc744fab5e7a9f35b0afa33.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/68e7a68728494e21a277d119bdbb4d75.png)
(Ⅱ)记数列
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/fbc8236c2c4f4a3091f5f8b59fd1259b.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/ee210b0a185f4b8eae2ab4ec19921647.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/a4562a6e231e4d7a9e379e16fc796ccd.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/067b2bb95ee14b36b0007f25b1684f14.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/475eb44d2ebf4c24a6141c71205e1d87.png)
![](https://img.xkw.com/dksih/QBM/2015/7/15/1572181905178624/1572181910626304/STEM/77b584f2569c4a9089ec149633a9f5bc.png)
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2016-12-03更新
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2卷引用:2015届吉林省实验中学高三上学期第五次模拟考试文科数学试卷