名校
解题方法
1 . 已知数列
,
的通项公式分别为
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be44e3dd1e96c5eb6cb04aeda7e228ac.png)
.
(1)数列
的前n项和为
,求
;
(2)在数列
中,已知
,是否存在正整数m,使得对于一切的
都有
恒成立?若存在,求出m的值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5538db8c14e5c8d5a11ec6740c862ed5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be44e3dd1e96c5eb6cb04aeda7e228ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9fc82353331abee0828dee9b38c08f2.png)
(1)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b91adba8efbf964e9e35547b0fd0ea36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9221c0c92a526f65533cdc5400767af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08db67992f06809a056f05baed620bf7.png)
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