已知等差数列
的前
项和为
,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/881e0a0ad1894dc926fa1b4ddf3a974e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.png)
更新时间:2020-05-31 18:40:07
|
相似题推荐
填空题-单空题
|
较易
(0.85)
【推荐1】二十四节气作为我国古代订立的一种补充历法,在我国传统农耕文化中占有极其重要的位置,是古代劳动人民对天文、气象进行长期观察、研究的产物,凝聚了古代劳动人民的智慧.古代数学著作《周髀算经》中记载有这样一个问题:从夏至之日起,小暑、大暑、立秋、处暑、白露、秋分、寒露、霜降、立冬、小雪、大雪这十二个节气的日影子长依次成等差数列,若小暑、立秋、白露的日影子长的和为
尺,霜降的日影子长为
尺,则秋分的日影子长为_______________________ 尺.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b837fd9c52f60bfb3b6852733abc790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
您最近一年使用:0次
填空题-单空题
|
较易
(0.85)
【推荐2】在等差数列
中,
为
的前
项和,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fee6adf04d7fbc48556ec949e89cc8b6.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/e557d3022a6dca4c61959ce77fa80799.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
您最近一年使用:0次
填空题-单空题
|
较易
(0.85)
名校
解题方法
【推荐1】已知等差数列
的通项公式为
.则数列
的前n项和![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7978d7bd6f6caf9ac9837ffce5f89654.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d7df34311bb06ffd80ecec159707470.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b91adba8efbf964e9e35547b0fd0ea36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7978d7bd6f6caf9ac9837ffce5f89654.png)
您最近一年使用:0次
填空题-单空题
|
较易
(0.85)
解题方法
【推荐2】已知等差数列
的前
项和为
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b227cd8bef7138ff72e89a09efb2fd8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.png)
您最近一年使用:0次