已知等差数列
的前n项和为
,
,
,使
的n的最大值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99e74f4453c367113388479505707b5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49763402b2f2023f0ba64c37924267d3.png)
A.8 | B.9 | C.14 | D.15 |
更新时间:2024-05-25 18:27:00
|
相似题推荐
单选题
|
较易
(0.85)
名校
【推荐1】已知两个等差数列
和
的前n项和分别为
和
,且
,则使得
为整数的正整数n的个数是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bee4464b3b4eb6e52ee02f095aae84f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aadd51d72723320ae712a8a7622551cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a31709d304949bd0f9bb4be389f3329b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1ec9880b7200e08f15ad22b8f374b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/feb8f04838c1533dc2aad1242a9257e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
A.6 | B.4 | C.3 | D.2 |
您最近一年使用:0次
单选题
|
较易
(0.85)
【推荐2】在中国古代,人们用圭表测量日影长度来确定节气,一年之中日影最长的一天被定为冬至.从冬至算起,依次有冬至、小寒、大寒、立春、雨水、惊蛰、春分、清明、谷雨、立夏、小满、芒种这十二个节气,其日影长依次成等差数列,若冬至、立春、春分日影长之和为31.5尺,小寒、雨水、清明日影长之和为28.5尺,则谷雨日影长为( )
A.8.5尺 | B.7.5尺 | C.6.5尺 | D.5.5尺 |
您最近一年使用:0次
单选题
|
较易
(0.85)
名校
解题方法
【推荐1】设
为等差数列
的前
项和,且
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7695d7b6905ff9d4cd9b063028cc092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f21c9c920ec8bc13650e9b2f455290.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5731f65834e58bb01c8d21a695e395ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bb7147e313f9d9f67d19ecb5f499c05.png)
A.75 | B.141 | C.7 | D.99 |
您最近一年使用:0次
单选题
|
较易
(0.85)
名校
解题方法
【推荐2】已知等差数列
满足
,
,则数列
的前10项的和等于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e82b67d4c44a0adf7eb7907731ee9629.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7d5c9abd937e015219fb01194ea74f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
A.10 | B.11 | C.100 | D.110 |
您最近一年使用:0次