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1 . 已知下列四个命题:
①等差数列一定是单调数列;
②等差数列的前
项和构成的数列一定不是单调数列;
③已知等比数列
的公比为
,若
,则数列
是单调递增数列.
④记等差数列的前
项和为
,若
,
,则数列
的最大值一定在
处达到.
其中正确的命题有_____ .(填写所有正确的命题的序号)
①等差数列一定是单调数列;
②等差数列的前
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
③已知等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eda6dc559d07bc22c9a0ed1e3a6d01d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
④记等差数列的前
![](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/b7bba46b546008abf9fcbb0db513385f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a417c950a40d58b01af28d2b9a57510e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ef7ca2b3e8061384501f668e59696a1.png)
其中正确的命题有
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2 . 若等比数列
的前
项和为
,已知
,
成等差数列,则数列
的公比为__________ .(用数字填写)
![](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)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92d800232ed782cdc72e45c679be7a0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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2019-03-08更新
|
504次组卷
|
2卷引用:天津市红桥区2018-2019学年高二上学期期末数学试题
23-24高二上·全国·课后作业
3 . 已知
,
为等差数列
的图象上的两点.
(1)求数列
的通项公式;
(2)画出数列
的图象;
(3)判断数列
的单调性.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/929a5a2d5fdcb44684f2408a251f1e66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66ea9c86a4cc05d5c95c134edb874e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)画出数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(3)判断数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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21-22高二·江苏·课后作业
4 . 已知等差数列的通项公式为
,求它的首项和公差,并画出它的图象.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/defc32c71990959534c3b4ada0b2ad54.png)
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20-21高二·全国·课后作业
解题方法
5 . 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?
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