解题方法
1 . 数列{an}中,如果an=49﹣2n,则Sn取最大值时,n等于( )
A.23 | B.24 | C.25 | D.26 |
您最近一年使用:0次
2020高三上·全国·专题练习
名校
解题方法
2 . 若公差为负的等差数列
中的两项
是方程
的两个根,设数列
的前
项和为
,则当
最大时,
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6387270759e4b23f0d9f44a4e0450562.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/043dd2ff2bcf103f3a7d507a02a35135.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/606e55241a2e145d54849129b8ffd20f.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.5 | B.9或10 | C.10 | D.9 |
您最近一年使用:0次
20-21高三上·河南·阶段练习
3 . 在递减等比数列
中,
,
是方程
的两根,若数列
前
项积为
,则当
取得最大值时,
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/682bf190fe598c0a653026c14dfe256f.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/392a8f641017f5df07890012bd80eec6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.4 | B.5 | C.6 | D.5或6 |
您最近一年使用:0次
4 . 已知递减的等差数列
满足
,则数列
的前n项和取最大值时n=( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c8a6d26b4d477496c1a810f414eaea1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
A.4或5 | B.5或6 | C.4 | D.5 |
您最近一年使用:0次
2020-12-23更新
|
640次组卷
|
4卷引用:河南省洛阳市2020-2021学年高二第一学期期中考试数学(文)试题
河南省洛阳市2020-2021学年高二第一学期期中考试数学(文)试题河南省洛阳市2020-2021学年高二第一学期期中考试数学(理)试题(已下线)专题4.2 等差数列(B卷提升篇)-2020-2021学年高二数学选择性必修第二册同步单元AB卷(新教材人教A版,浙江专用)江苏省苏州市常熟市2021-2022学年高二上学期期中数学试题
5 . 已知等差数列
的前n项和为
,若
,
,则( )
![](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/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d35ade9a4a68d094a4299d0b7c2a767.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
您最近一年使用:0次
名校
解题方法
6 . 设等差数列
的前
项和为
,
且
,则当
取最小值时,
的值为( )
![](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/179513ce80436471efbe1d9b31735f7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d88062de27fcd3a6789a3b6e7170ce56.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
2020-12-05更新
|
1085次组卷
|
3卷引用:甘肃省永昌县第一中学2020-2021学年高三上学期第一次月考数学理试题
解题方法
7 . 下列说法中正确的是( )
A.数列![]() | B.数列![]() |
C.数列![]() | D.数列![]() ![]() ![]() |
您最近一年使用:0次
8 . 已知在数列
中,对任意的
,
恒成立,当且仅当
时,
取得最小值,且
,则满足上述条件的
的个数为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cc105f00bf48b0f228f411ab7b5c999.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fac3649308b528fd56545ba102dc42d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7853f405ef98a2c81c1c66a1288b0e3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
A.1 | B.2 | C.4 | D.5 |
您最近一年使用:0次
2020-12-02更新
|
264次组卷
|
2卷引用:河南省豫南九校2020-2021学年第一学期高二第三次联考(11月)理数试题
解题方法
9 . 已知公差不为0的等差数列{an}的前n项和为Sn,a1=2,且a1,a3,a4成等比数列,则Sn取最大值时n的值为( )
A.4 | B.5 | C.4或5 | D.5或6 |
您最近一年使用:0次
10 . 已知公差不为0的等差数列
的前n项和为
,
且
成等比数列,则
取得最大值时n的值为( )
![](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/fbcb3d9ff9a4c566c638cd0ef0340d34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ffbddc2f4fc02740d470a67774b77f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
A.4 | B.5 | C.4或5 | D.5或6 |
您最近一年使用:0次
2020-11-15更新
|
193次组卷
|
2卷引用:湖南省三湘名校教育联盟2020-2021学年高二上学期期中数学试题