1 . 已知
是2和4的等差中项,正数
是
和
的等比中项,则
等于__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274a9dc37509f01c2606fb3086a46f4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6b9a5f1362c12e1ea8f6fc0d9d787ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18f0281e6bbdbe08beeccb55adf84536.png)
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解题方法
2 . 已知等差数列
的前
项和为
,且
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7999465d0e871febde66296a0cbf058c.png)
________
![](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/318a55dd52cc22c391f6640ac2560420.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52ff4f2d9a76730a7ff5baf43da46f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7999465d0e871febde66296a0cbf058c.png)
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3 . 写出一个同时具有下列性质①②③的数列
,①无穷数列;②递减数列;③每一项都是正数,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
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2021-10-07更新
|
1215次组卷
|
8卷引用:广西桂林市第十八中学2021-2022学年高二上学期开学考试数学(文)试题
4 . 记
为等差数列{an}的前n项和.若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4259345a7b1964a756911dbe0ed9ee42.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ef0f4a21029a041976b8d86257e7666.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4259345a7b1964a756911dbe0ed9ee42.png)
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名校
5 . 数列
是等差数列,
,则其前5项和![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614306cc3f34bdee4d5d885b79667645.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae02b7678da9ab6f2e0e65df2bad41e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614306cc3f34bdee4d5d885b79667645.png)
您最近一年使用:0次
2021-07-15更新
|
328次组卷
|
2卷引用:广西壮族自治区桂林市桂林中学2021-2022学年高二上学期开学考试数学试题
6 . 已知数列
的前
项和为
,
,设数列|
的前
项和为
,若
对任意的
恒成立,则实数
的取值范围为______ .
![](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/4300dca231e2f4b37f70900b33439d5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba57c83d526ac308d1461e80fcca9f36.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/997924336512ec08b4ff5d8221f609d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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7 . 若等比数列
的各项均为正数且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1894b67d483f97ec4aff564a81cc6da2.png)
_____ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/975e18ef7e59bc76e681d291a525e348.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1894b67d483f97ec4aff564a81cc6da2.png)
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2021-02-05更新
|
720次组卷
|
3卷引用:广西桂林市2020-2021学年高二年级上学期期末数学(理)试题
名校
解题方法
8 . 数列
的前
项和
满足
,则数列
的通项公式![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.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/c8370a173854471a3eb27637993a3d5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
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2020-11-28更新
|
941次组卷
|
4卷引用:广西桂林市2020-2021学年高二上学期期末数学(文)试题
9 . 数列
的通项公式
,则该数列的前
项之和等于______________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c5034a6a8063b7547521fec1cabeda0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
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2020-01-08更新
|
270次组卷
|
3卷引用:广西桂林市桂电中学2021-2022学年高二上学期期中数学试题
11-12高一下·浙江舟山·阶段练习
名校
解题方法
10 . 已知数列
中,
,
,则数列
的通项公式为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbe7bdaaf8b0adf10bf2ef6c1255b1dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1542d9b47ed2fc91e0a0275f1dba4254.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
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2020-08-12更新
|
140次组卷
|
9卷引用:广西桂林市中山中学2021-2022学年高二上学期期中质量检测数学(理)试题
广西桂林市中山中学2021-2022学年高二上学期期中质量检测数学(理)试题(已下线)2011-2012学年浙江岱山大衢中学高一5月月考数学试卷(已下线)2012-2013学年云南省昆明三中、滇池中学高一下学期期末考试数学卷2014-2015学年贵州省绥阳中学高一下学期第三次月考数学试卷黑龙江省双鸭山市第一中学2016-2017学年高一下学期期末考试数学(文)试题【全国百强校】陕西省西安交通大学附属中学2016-2017学年高一下学期期中考试数学(理)试题辽宁省大连市旅顺口区2018-2019学年高一下学期期末数学(文)试题(已下线)2.2等差数列(1) -2020-2021学年高二数学课时同步练 (人教A版必修5)(已下线)4.2.1 等差数列(1)-2020-2021学年高二数学课时同步练(人教A版选择性必修第二册)