4.2.2 等差数列的前n项和(1)
重点练
一、单选题
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d737c1047a14cee12a6671383e244fa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7915c727224ffdad17a0a17e6c73087d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eed39c7d611309b01476c15ab242308.png)
A.18 | B.36 |
C.54 | D.72 |
【知识点】 等差数列前n项和的基本量计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/514b1debe4e2684efb37a743cd24194e.png)
A.![]() | B.![]() | C.![]() | D.![]() |
【知识点】 等差数列通项公式的基本量计算 含绝对值的等差数列前n项和
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb4322516aa4b45c3d5d256a2aab12ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ea8f24340dc4c83c7dd6f796cef5f64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05201ef79a5d5904f492845396fb5470.png)
A.66 | B.99 | C.144 | D.297 |
【知识点】 利用等差数列的性质计算 求等差数列前n项和
二、填空题
【知识点】 等差数列前n项和的基本量计算 等差数列奇数项或偶数项的和
三、解答题
(1)若a3=4,求{an}的通项公式;
(2)若a1>0,求使得Sn≥an的n的取值范围.
【知识点】 等差数列前n项和的基本量计算