设等差数列
的前n项和为
,且
,
.求
的通项公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d9407c15370762cfdb972f7044cc650.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baf47f2573dea01b5de55b87c3f7fd0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
更新时间:2022-07-07 23:55:56
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相似题推荐
解答题-问答题
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解题方法
【推荐1】已知等差数列
,
,
,
(1)在区间
上,该数列有多少项?
(2)在区间
上,该数列有多少项能被
整除?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88ce87642d4f11148b5d8e65018431b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c942ba8e169307b51c06db4b56a7e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52ed857e43f854552ca346e15164ad7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
(1)在区间
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7095ffc653ec181c33fa70b869dc760.png)
(2)在区间
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7095ffc653ec181c33fa70b869dc760.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
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解题方法
【推荐2】已知各项都是正数的数列
的前
项和为
,
,
.求数列
的通项公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.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/a3676c51d6987107ebd4aadbffd82abc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f093c61867ee4ce75f951d46b9b123.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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解答题-问答题
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(0.85)
【推荐1】已知等差数列
中,
,前
项和
.
(1)求通项
;
(2)若从数列
中依次取第2项、第4项、第8项…第2n项……按原来的顺序组成一个新的数列
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29518f13a1ebc3fff8181c2d7cfba22f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45ae63f39cda2e68ed7abc1dc3311987.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f43677db00ba65a7f96fc49627d70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1085f321e73ca82a9f391550226ee822.png)
(1)求通项
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bfccafa83afe5ee21eab6ef2b2c8852.png)
(2)若从数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29518f13a1ebc3fff8181c2d7cfba22f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2448cf72af76b810310e4cfb9818e2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2448cf72af76b810310e4cfb9818e2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb26cd1601fe7e76e1e2dc0b4909324a.png)
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名校
解题方法
【推荐2】已知等差数列
的前
项和为
,且满足
,
.
(1)求数列
的通项公式;
(2)记
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.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/668144ced4514790322b1d1421f5ed65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8af92c06ea15668b9fe91c97fcc6a21.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e5f5061101ed3fc39e89d4c9097787f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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