名校
1 . 已知数列
和
,其中
,当
时,试比较
与
的大小,并用数学归纳法证明你的结论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f1ce1d77a0a00432fccf2a0b3b85dc8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dea0dab63dac92bedf9fd37c3e80c076.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36b98ef143f8159f3a7dafa1fd2f2370.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/686ece75006ad358f23314dc8a246e11.png)
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解题方法
2 . 已知数列
的前n项和为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/016c31f6fd165bc81a76956da545029f.png)
,令
.
(1)求证:数列
是等差数列,并求数列
的通项公式;
(2)若![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf21791a47151bfee683e95ffee1bdcf.png)
,用数学归纳法证明
是18的倍数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/016c31f6fd165bc81a76956da545029f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d5fa85887816de29bcff4f143e3f0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f32322ce51946bd1078748378816c7.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf21791a47151bfee683e95ffee1bdcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d5fa85887816de29bcff4f143e3f0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d4fc8faefb26b233d4aa9dbef043aae.png)
您最近一年使用:0次