已知等差数列
的前n项和为
,
,且
.
(1)求
;
(2)求数列
的前n项和
.
![](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/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14b96df95bc37e6951c12c417ece4b71.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfbf82935deed70b40b23725a2617fdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
更新时间:2019-11-05 13:31:19
|
相似题推荐
【推荐1】在①
;②
,
;③
,
这三个条件中任选一个,补充在下面问题中,然后解答补充完整的题目.
问题:已知
为等差数列
的前n项和,若 .
(1)求数列
的通项公式;
(2)设
,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/57c599e7cec6d192fb73218e7882ceca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1928c254cfada1f75a5cd1e34db5a63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebfd6e425411179e2a5a06d84978356e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13a6e1d671215fc96e4bee3541d1096.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e26faf2d524402fefa06823506d1971.png)
问题:已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad91ad3b1d320c2115369d0e960a373f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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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(0.65)
名校
【推荐2】已知
为等差数列,且
,
.
求
的通项公式;
若等比数列
满足
,
,求
的前n项和公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d2348d5068480809ea002ebc2d3261b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cb9ba63984a3f27de68e59973024c44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c7396497bee48d7ca67c99061d703fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4141b26d2c32655003494a91ad6331b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d2348d5068480809ea002ebc2d3261b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65863c1abad833b79c303bfca24f535c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37ad1fb1d7620bbe82f7b2fc898884a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2612dbbb244e5453b0188719410fbf21.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3297d95e8119509bd42f8ded2cef3aee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37ad1fb1d7620bbe82f7b2fc898884a3.png)
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解题方法
【推荐1】设数列
的前
项的和
满足
,等比数列
满足
.
(1)求数列
,
的通项公式;
(2)求数列
的前
项的和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4300dca231e2f4b37f70900b33439d5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43b7e7cd571c8cd141cbbfe5d0890bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3c9dd662208f828e7fc8a753443273b.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43b7e7cd571c8cd141cbbfe5d0890bf6.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/731e60bc5b0bd0b66a3ebb2b73b5d2cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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解题方法
【推荐2】各项均为正数的等比数列
中,
,
.
(1)求
的通项公式;
(2)设m为整数,且对任意的
,
,求m的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/471584358a4c23a08378b2d8fa02c8c4.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设m为整数,且对任意的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a759b5f85619c2445544057056d5c492.png)
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