在等差数列{
}中,
=1,前n项和为
,有2S=
(n
),
(1)求
;
(2)若
=
,当n<19, n
时,试比较
…
和
…
的大小
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abc35db70903a914dbe0b6c07e9b341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ff6d85a34308b49955202cefe3c78c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/227f8d6f935a4e9fbe2098e2f0d16c2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e135c621652113201fcd8102aa4c3f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d0d3ea3cd011ff255950d54d30d5ea7.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4408cd06f655faa6981a866cdd30c625.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b56c50cf9d757e5ea8e7009a339a81af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97d3ddd240a8127e9c11e5d8c4929a74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d0d3ea3cd011ff255950d54d30d5ea7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b5bf43f270489ff9c228a14d59421e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b56c50cf9d757e5ea8e7009a339a81af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b5bf43f270489ff9c228a14d59421e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7db7647f448cca4308cbda6c37d20f9.png)
更新时间:2018-04-11 19:26:33
|
相似题推荐
【推荐1】设
是等差数列,
是各项都为正数的等比数列.且
,
,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
(1)求
,
的通项公式;
(2)记
为
的前
项和,求证:
;
(3)若
,求数列
的前
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.
![](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/ebaf2a2590bb84d646957f913d78f6dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/431d1949ced5df0568a4c386a6c99ecd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d936e2b8dc747af717d03452795b908f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.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/f3a868ca08b79f3416de960cbf1016bd.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf4fb0efe2f7d2e9da69827a8154065f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b9a0d7150fb24be3e28ef7f0e18be93.png)
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解答题-问答题
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适中
(0.65)
【推荐2】数列
、
的每一项都是正数,
,
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、
、
成等差数列,
、
、
成等比数列,
.
![](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/2cdf53108bee755f5aa9a34ea4d163e4.png)
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(Ⅰ)求、
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(Ⅱ)求数列、
的通项公式;
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解答题-问答题
|
适中
(0.65)
名校
【推荐1】已知正项数列
,其前
项和为
.
(1)求数列
的通项公式:
(2)设
,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)
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(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69ccc608700aeed317c351ec6ed9156f.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)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
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)是否存在非零常数
使数列
为等差数列?若存在,请求出
;若不存在,请说明理由.
![](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/5caf56d06f90369f945b8165cc0e82af.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)是否存在非零常数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8609cdf0315dcfdbc10a8729b8b77af9.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1】已知等比数列
满足
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(1)求
的通项公式;
(2)设
,求
的前
项和
.
![](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/3768c7d63270423d6e7e5dc591964bc3.png)
(1)求
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(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70e760fd67663947e5bd1800efdae057.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/08eb71ecf8d733b6932f4680874dbbf3.png)
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【推荐2】图中的数阵满足:每一行从左到右成等差数列,每一列从上到下成等比数列,且公比均为实数
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/7/6f057cc0-3d41-4376-8ed2-a8130b528680.png?resizew=174)
(1)设
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(2)设
,是否存在实数
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恒成立,若存在,求出
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![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/7/6f057cc0-3d41-4376-8ed2-a8130b528680.png?resizew=174)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21bf0b36adf8adffb0918c31df2783ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
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