1 . 已知
是等差数列,a5=15,a10=-10,记数列
的第n项到第n+5项的和为Tn,则
取得最小值时的n的值为_____ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49c991692d281ea8c2fda692113809f2.png)
您最近一年使用:0次
2 . 在等差数列
中,已知
,前
项和为
,且
,则
的最大值是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cceacfd0395da804e9fd4878fbd93080.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/19557eeb69331a65fa03fa64c4a41654.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.110 | B.120 | C.130 | D.140 |
您最近一年使用:0次
名校
3 . 若![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e45bcd8f6ede8cc2513ad41402f40086.png)
为等差数列,
为其前n项和,若首项
,公差
,则使
最大的序号n为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e45bcd8f6ede8cc2513ad41402f40086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06dd3c3b45125d4b484e2894992610f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9f55505fb7feb499bd254acc7853b66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.2 | B.3 | C.4 | D.5 |
您最近一年使用:0次
2016-12-03更新
|
559次组卷
|
2卷引用:2015-2016学年湖南师大附中高二上学期期中文科数学试卷
解题方法
4 . 已知数列
是等差数列,其前
项和为
,若首项
且
,有下列四个命题:
;
;
:数列
的前5项和最大;
:使
的最大
值为10;
其中正确的命题个数为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.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/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83fa8beb4c49deeb32de236126b488d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54c01d9d2fdc778aef8f6c4b4974ad0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6c175dedaf61348bf2045e92f946dd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/797e67927616b141ed7c6b83f8b6f4fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fee50575e3ebd56c4f46dd0bbf8e55d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49763402b2f2023f0ba64c37924267d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
其中正确的命题个数为( )
A.1个 | B.2个 | C.3个 | D.4个 |
您最近一年使用:0次
名校
5 . 等差数列
中,
,若其前
项和为
,且有
,那么当
取最大值时,
的值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d157b8c366da862bb263221f2c566f5f.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/1e42ae098081fc35f91d4bb8e8908a41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.8 | B.9 | C.10 | D.11 |
您最近一年使用:0次
2016-12-03更新
|
928次组卷
|
6卷引用:2014-2015学年福建省德化一中高一下学期期末质量检查数学试卷
6 . 等差数列
的前
项和
,若
,
,则
的最大值是___
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.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/6df1038200f2d97a52c716aab6c3bcb6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd67cf18bd35149475d35f1c603ad59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
7 . 等差数列
中,
,
是前
项和且
,则当
( )时,
最大.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/390636a89883bd64bf8da9bf8654aff9.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/c6cd1fa5c3b16db023420ab14cd4f938.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.12 | B.13 | C.12或13 | D.13或14 |
您最近一年使用:0次
13-14高一下·浙江湖州·期中
8 . 等差数列
中,
,公差
,那么使
的前
项和
最大的
值为
![](https://img.xkw.com/dksih/QBM/2015/7/3/1572164948549632/1572164954021888/STEM/92d38f15d7734112a0886a079fc03e70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bfeb12b4aee769abe59c795f59d46df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f2a482b048ada7bc981a416116fa2b6.png)
![](https://img.xkw.com/dksih/QBM/2015/7/3/1572164948549632/1572164954021888/STEM/92d38f15d7734112a0886a079fc03e70.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)
A.![]() | B.![]() | C.![]() ![]() | D.![]() ![]() |
您最近一年使用:0次
2016-12-03更新
|
524次组卷
|
3卷引用:2013-2014学年浙江省湖州市属九校高一下学期期中考试数学试卷
(已下线)2013-2014学年浙江省湖州市属九校高一下学期期中考试数学试卷2014-2015学年浙江省台州中学高一下学期期中考试数学试卷苏教版(2019) 选修第一册 一蹴而就 第4章 4.2.3 等差数列的前n项和
解题方法
9 . (1)设数列
满足:
,
,
.求
的通项公式及前
项和
;
(2)已知数列
的前
项和为
,且
,求
的最大值和通项
.
![](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/106d71d47fffa137648f8cf30309e384.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29d5ec9ad92f37e64eccce922ab1b14e.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)
(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/95c5fbbc357da8232c84131e2d4d3fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/686ece75006ad358f23314dc8a246e11.png)
您最近一年使用:0次
10 . 设等差数列
的前n项和为
,已知
,当
取得最小值是,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce855eb256dfdd3250e85106807cc50e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
A.5 | B.6 | C.7 | D.8 |
您最近一年使用:0次
2016-12-03更新
|
930次组卷
|
6卷引用:2015届山东省潍坊市高三上学期期中考试理科数学试卷
2015届山东省潍坊市高三上学期期中考试理科数学试卷2015届山东省潍坊市高三上学期期中考试文科数学试卷2015-2016学年江西省上高二中高一上学期期末数学试卷(已下线)2018年高考二轮复习测试专项【新课标理科】热点五 数列中的最值问题(已下线)2018年高考二轮复习测试专项【新课标文科】热点五 数列中的最值问题重庆市江津第六中学2018-2019学年高一下学期期中数学试题