若
为数列
的前n项和,
,且
.
(1)求数列
的通项公式;
(2)若
,求数列
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c15b38e42490c65be958f53c40f6fd7.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f2b90df8cdcf57a6eb7a60e5ee9fcdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da72309d2507e2f5e5ed88d8cc08963.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
2022·青海西宁·三模 查看更多[2]
更新时间:2022-06-06 21:45:58
|
相似题推荐
【推荐1】已知数列{
},
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(1)证明{
}是等比数列;
(2)求数列{
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
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(1)证明{
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(2)求数列{
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【推荐2】已知数列
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
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解题方法
【推荐1】已知数列
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
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(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6dcba920904a03e3f950e962cc8c7ad.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6630dc9ef5994449980ab0924f9d2fe7.png)
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您最近一年使用:0次
解答题-问答题
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适中
(0.65)
【推荐2】已知数列
的前
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;.
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的前
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(1)求数列
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(2)求数列
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您最近一年使用:0次
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解题方法
【推荐1】在①
,
②
,③
这三个条件中任选一个补充在下面的问题中,并加以解答.
设等差数列
的首项
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项和为
,若 ,.
(1)求数列
的通项公式;
(2)记
,求数列
的前n项和
.
注:如果选择多个条件分别解答,按第一个解答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c9ceb26e76b084f69e0930d28659fed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80533fb0ee88b28ad9a0c5725ba9b3d7.png)
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设等差数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
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注:如果选择多个条件分别解答,按第一个解答计分.
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适中
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【推荐2】设数列
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(
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(
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