对于数列
,如果
为等差数列,则称原数列
为二阶等差数列,一般地,如果
为
阶等差数列,就称原数列
为
阶等差数列.现有一个三阶等差数列,其前7项分别为1,5,11,21,37,61,
,则该数列的第7项为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d82c65a855b1eed9c43e6829f6c3bffb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d82c65a855b1eed9c43e6829f6c3bffb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0acfbe600b6693d767b3ab194f8d172f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
A.101 | B.99 | C.95 | D.91 |
更新时间:2022-03-20 07:35:33
|
相似题推荐
单选题
|
适中
(0.65)
解题方法
【推荐1】已知数列
的前
项和为
,
,
,
,下列说法不正确的是( )
![](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/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfb935f051b32f2aa848b4ec9b54ca6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
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解题方法
【推荐2】已知直线
,其中
是公差为5的等差数列
的第
项,在直角
中,
,则
面积的最小值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/328aa79961d8a3d8251480d4f717228a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50a272adba0f1120109824440f0e252c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c05b9832b09731a574d4a4adf7448de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a7bf13a408071d4d92f86c22ec78108.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
A.2 | B.1 | C.![]() | D.![]() |
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【推荐1】定义:在数列
中,若满足
(
为常数),称
为“等差比数列”,已知在“等差比数列”
中,
,则
等于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a3871f856cd942afc1057a8e1e35ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c64e5abbc7b55e2fd5904aae6892c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a4970320426dc9117a94237e607475f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c0783de13d04423c1c9202310aec488.png)
A.4×20162-1 | B.4×20172-1 | C.4×20182-1 | D.4×20182 |
您最近一年使用:0次
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【推荐2】对于数列
,定义
为数列
的“美值”,现在已知某数列
的“美值”
,记数列
的前
项和为
,若
对任意的
恒成立,则实数
的取值范围是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0475b4fd318c7d0111a722258f8923bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b9aced2ea017eed5c456754d4ee178.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c58bea74df90e831c83a88cadd7e7ccd.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/bbe5cd2ab0f41e27bfbf8d7abd3b92bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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