已知函数
,且
的解集为
,数列
的前
项和为
,对任意
,都有![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7258b3bad12e61e6a7e666757b2c752.png)
(1)求数列
的通项公式.
(2)已知数列
的前
项和为
,满足
,
,求数列
的前
项和
.
(3)已知数列
,满足
,若
对任意
恒成立,求实数
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fdad1e5b53f816db7b5f092357e040a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a71baf6217604517fd98fa97d0f55b43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c47bebfa5c1ee08c44271d443cd041.png)
![](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/b2aa78c96db411c9e1e939ae16de78d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7258b3bad12e61e6a7e666757b2c752.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)已知数列
![](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)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58ea95825136ea3d7c56e697d9512d5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2aa78c96db411c9e1e939ae16de78d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec4bdc2a6d4fc387dc621f0b5a268c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cfeacc29e6a61c5b3b4e439c0a91df.png)
(3)已知数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e02e5723a6a543b985bbfad7f8af3b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2d9a8ee84e96e88dd5362054fb2e71e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2aa78c96db411c9e1e939ae16de78d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
更新时间:2020-02-19 11:59:50
|
相似题推荐
解答题-问答题
|
适中
(0.65)
真题
【推荐1】设数列
满足
.
(1)证明:
对一切正整数n成立;
(2)令
,判断
与
的大小并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4816e2d68067ccbe20e9b094e164b743.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b82d9ebbf2807336d9d9fe2f142669d.png)
(2)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3191e5b0531d1a13aa5c0c4586885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/686ece75006ad358f23314dc8a246e11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e95931effbd59c43e8ed1ea09962b84f.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐2】已知数列
的前
项和为
,且
.
(1)设数列
满足
,证明:数列
是等比数列;
(2)求
为多少时,
取得最小值?
![](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/059ab26ac63cc1376743db1a4e7da17d.png)
(1)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f3e24b4df66fe8c7eff9241ab6ad569.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
【推荐1】已知数列
的前
项和为
,且对任意正整数
,都有
.
(1)求数列
的通项公式
;
(2)若数列
满足
,
,求数列
的最大项;
(3)若数列
满足
,且对任意的正整数
,不等式
恒成立,求实数
的取值范围.
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3399581f68e9f834cc2c7a85bb5186e.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59dd6c97d2ee3e74ba5730f1cbcc1d43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9087b22d831eb8976b1d75ae68372d3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(3)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb856ca78ed069612b4b4feb7e4ed659.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d68bd8f152cf0d50cade62deb0c75cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
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解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】已知数列
满足
是正整数
(1)求数列
的通项公式;
(2)设
,如果对于任意正整数
,都有
,求实数
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81442f17bd9d039d001a7511f4fd1064.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad2c057d0a60c7f305436f1d7bd5a759.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd624bda9f45309816fc1e6f27e42675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐1】等差数列
的公差d不为0,其中
,
,
,
成等比数列.数列
满足![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7048789f99a8fa350e8ac5e9c22ddc71.png)
(1)求数列
与
的通项公式;
(2)若
,求数列
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6278d3cc0086c7aab6ac20712c7d0bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da4cd81500bdb43118150dbdb1541e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7048789f99a8fa350e8ac5e9c22ddc71.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac07953530e3c248b3438fb200fb1661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
【推荐2】在高中的数学课上,张老师教会了我们用如下方法求解数列的前n项和:形如
的数列,我们可以错位相减的方法对其进行求和;形如
的数列,我们可以使用裂项相消的方法对其进行求和.李华同学在思考错位相减和裂项相消后的本质后对其进行如下思考:
错位相减:设
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5e0b97655e9eb5c87997617d282f6eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e1d40988654589127e817be51de3ad8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14f5da1800978ef919998b6309698275.png)
综上:当中间项可以相消时,可将求解
的问题用错位相减化简
裂项相消:设
或
为公比为1的等比数列;
①当
时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63458c14477896f2e6ad6cb098631e27.png)
②当
为公比为1的等比数列时,
;
故可为简便计算省去②的讨论,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/014fb61c8d5b4529152136e53069a47c.png)
综上:可将求解
的问题用裂项相消转化为求解
的问题
你看了他的思考后虽觉得这是“废话文学”,但是你立刻脑子里灵光一闪,回到座位上开始写下了这三个问题:
(1)用错位相减的方法“温故”张老师课堂上举的例子,求解数列{
}前n项和
;
(2)用裂项相消的方法“知新”张老师课堂上举的例子,求解数列{
}前n项和
;
(3)融会贯通,求证:
前n项和
满
.
请基于李华同学的思考做出解答,并写出裂项具体过程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa4af777bba4bcd527c24abbedf3fc7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec4f94ae2cd72cf8d08f45c33e1df1ec.png)
错位相减:设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/243188b27b9134497a6068c46d35c61a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5e0b97655e9eb5c87997617d282f6eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e1d40988654589127e817be51de3ad8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14f5da1800978ef919998b6309698275.png)
综上:当中间项可以相消时,可将求解
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
裂项相消:设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a5acd834d711c8970d59337500938d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44cb6d263dc6899b5eff27ab7fbe2fbf.png)
①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4773153ca64ad98a61993a1865371ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63458c14477896f2e6ad6cb098631e27.png)
②当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44cb6d263dc6899b5eff27ab7fbe2fbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3087fa280904de01dcaa471422f571f.png)
故可为简便计算省去②的讨论,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/014fb61c8d5b4529152136e53069a47c.png)
综上:可将求解
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bbbf4d763f3cbe5a71707bc19c78191.png)
你看了他的思考后虽觉得这是“废话文学”,但是你立刻脑子里灵光一闪,回到座位上开始写下了这三个问题:
(1)用错位相减的方法“温故”张老师课堂上举的例子,求解数列{
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)用裂项相消的方法“知新”张老师课堂上举的例子,求解数列{
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(3)融会贯通,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f93623cab3bffa4d8aa946d7fa82e08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30f963db8a685e5ac27dfeee0153ed79.png)
请基于李华同学的思考做出解答,并写出裂项具体过程.
您最近一年使用:0次