解题方法
1 . 已知数列
是等差数列,其中
,
.
(1)求数列
的通项公式,并画出它的图象.
(2)数列
从哪一项开始小于0.
(3)求数列
前n项和的最大值,并求出对应n的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/008d0d4c22970d770c75589b380a37de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ddc6daf7e71ab940882c380f06e8908.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(3)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
您最近一年使用:0次
23-24高二上·全国·课后作业
解题方法
2 . 已知
为等差数列
的前n项和,且
,
.
(1)求数列
的通项公式;
(2)求
的最大值及对应的n值.
![](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/6be3f864d60fc147b6905979403f3b2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c9ad0c77cb1d6bdcee22768c59c12a4.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
2023-09-12更新
|
449次组卷
|
3卷引用:1.2 等差数列