已知数列
是正项数列,且
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/670579690fc05a060cae7129ff37350f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88a93cd933205ee6a5af0c514e14ca25.png)
A.216 | B.260 | C.290 | D.316 |
更新时间:2024-05-25 19:01:21
|
相似题推荐
单选题
|
适中
(0.65)
名校
【推荐1】已知函数
,若函数
的极大值点从小到大依次记为
,并记相应的极大值为
,则
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af8eefe962394107ade247185ab6a40f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7942d8b3fecb8c40b7be80434dc8a869.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bdc9bf74185d35a64d5ec5d8e299559.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49a40d27d6bbdc5aee21d8b72e364958.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
【推荐2】已知等差数列
公差为
,其前
项和为
,等差数列
公差为
,其前
项和为
,则下列命题中正确的个数是( )
①若
为等差数列,则
②若
为等差数列,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a143e66de2b0a9dd49e10752333be6a7.png)
③若
为等差数列,则
④若
,则
是公差为
的等差数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5edf900c810371fb21297c15f86d8743.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/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b31ac1def558351e2e3ed1235c570530.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/832d1e3a06f59a35396aac6e12c5e2ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5edef261fe3621693bfc241f13348042.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fa87cc289d1f05f710104238aafb426.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a143e66de2b0a9dd49e10752333be6a7.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dc0bdefe6ea4cc508dd42ee6061106b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff411af5d78f0e207047420baa2cd89d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35ebc5304d7aac9ffbbbd0f0b91d3daf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e8e3d93a73678ab186ea7951c39b841.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed7224e8252f5473afcda5462a4ebee6.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
单选题
|
适中
(0.65)
解题方法
【推荐1】定义
为
个正数
的“均倒数”,若已知正整数数列
的前
项的“均倒数”为
,又
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/328fc112e91d5247e5b0ef2966649aad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e9aeedd667b326db1c1401c9cc75c20.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/ea53ed018b5d74acdf3f167be78e067f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff4f1ef7f84973ca198606a6c76a2901.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a73cc4f4ac7d3819706b2c94302d5b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
单选题
|
适中
(0.65)
解题方法
【推荐2】已知数列
的前n项和
,则
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c0f2118f2771a5a347f7dab243417ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/341cbe301b048eb979e96f4a81440123.png)
A.68 | B.67 | C.65 | D.56 |
您最近一年使用:0次