11-12高一下·四川攀枝花·阶段练习
解题方法
1 . 等差数列
中,
,
,且
,
是前
项和,则下列判断正确的有_______ .
①数列
的最小项是
;
②
,
,
;
③
先单调递减后单调递增;
④当
时,
最小;
⑤
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88b8be47f727e800bef9b647254dd432.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b499db552a74e4d609391271dcf72ad2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de0db09c9753bb386bdf8fd9c7ae6dec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
①数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/486cddc710aec81c76b5b395446eaa00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ad3bdc2cf20eefdf5b999239cc6f935.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce868ac245a30cc99db2b35b2fabc545.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
④当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c345907ebe27888332b1b44c666cc47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
⑤
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb6ebaeb63ef37c1d92f44777ac97b58.png)
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12-13高一下·四川成都·阶段练习
2 . 等差数列
中,
;设数列
的前
项和为
,则![](https://img.xkw.com/dksih/QBM/2013/4/12/1571184111804416/1571184116867072/STEM/9f16053d828946f38c3615973bf08831.png?resizew=37)
______________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/890644ae83ebb3572c3d001a94de0b0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b91adba8efbf964e9e35547b0fd0ea36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://img.xkw.com/dksih/QBM/2013/4/12/1571184111804416/1571184116867072/STEM/9f16053d828946f38c3615973bf08831.png?resizew=37)
您最近一年使用:0次
10-11高三·山东烟台·阶段练习
3 . 设
表示等差数列
的前n项和,且
,若
,则n=__________
![](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/05af4ebcae6060073a1b4b3fcc8dc12b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa05a025c817a20fd6386b1e5130e32.png)
您最近一年使用:0次
解题方法
4 . 已知数列
为等差数列,前九项和
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b75ec86aa0e1fe86f6fdeee4ab26ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
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5 . 已知等差数列
的前
项和为
,且
,若
,则
的取值范围是_________ .
![](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/174e3890e2a7c0737fdd6bd595a488fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be894ff9823b4378b558a67e57e7b0c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
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名校
解题方法
6 . 两个等差数列
和
的前
项和分别为
、
,且
,则
等于___
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.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/1c0aa2cd1976a0ad08b9faab83384d87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae59e2a5fdc981b202b2735d9ce0eaf1.png)
您最近一年使用:0次