20-21高二·全国·课后作业
解题方法
1 . 已知数列{an}的前n项和为Sn,数列{an}为等差数列,a1=12,d=-2.
(1)求Sn,并画出{Sn}(1≤n≤13)的图象;
(2)分别求{Sn}单调递增、单调递减的n的取值范围,并求{Sn}的最大(或最小)的项;
(3){Sn}有多少项大于零?
(1)求Sn,并画出{Sn}(1≤n≤13)的图象;
(2)分别求{Sn}单调递增、单调递减的n的取值范围,并求{Sn}的最大(或最小)的项;
(3){Sn}有多少项大于零?
您最近一年使用:0次
2 . 设等差数列
的前
项和为
,若
,
,则当
取得最大值时,
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/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c98614b893bc98ede0f87d4b0a00cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
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解题方法
3 . 记
为等差数列
的前
项和,若
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.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/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd5ce002f88a27b0b151f5122c4cae26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
您最近一年使用:0次
2020-04-27更新
|
601次组卷
|
3卷引用:云南省弥勒市第一中学2020-2021学年高二下学期第三次月考数学(文)试题
名校
4 . 等差数列
与
的前
项和分别为
和
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54ab5cd1c10e1a71703d35e25003646f.png)
________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.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/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca151ab4c16326245115aee75e6c332e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54ab5cd1c10e1a71703d35e25003646f.png)
您最近一年使用:0次
2020-01-08更新
|
730次组卷
|
4卷引用:江苏省南通市启东市东南中学2021-2022学年高二上学期期中数学试题
江苏省南通市启东市东南中学2021-2022学年高二上学期期中数学试题上海市金山区华东师大三附中2019-2020学年高一下学期期末数学试题(已下线)上海市华东师范大学第二附属中学2015-2016学年高一下学期期末数学试题云南省昆明市官渡区尚品书院学校2022-2023学年高二上学期12月月考数学试题