1 . 已知数列
是等比数列,
,
,
,
成等差数列.
(1)求
的通项公式和
;
(2)数列
满足
;当
时,
;当
时,
.记数列
的前
项和为
.
①若
,求
的值;
②若
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61d473bfcc52ebc119430335531488a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8822db269777fddd605b50521576b57.png)
(2)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5adec817865eefb615fb692c4b7f473.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6f536ba19aa3c3b1be97b33dfd852f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f205eb08ae9ffe22dc6fbfe2b1fe65fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25b434cd915f3e6fbc3028f86f358332.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df3054785bacfe0537831c337f57ab92.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)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b54a7884388655cea734328f3e43f90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c59268f6dd353af2dedd8269a2bc5b77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d0f924858fdfc9403142fcbce46de32.png)
您最近一年使用:0次
2 . 已知数列
满足
,其前8项的和为64;数列
是公比大于0的等比数列,
,
.
(1)求数列
和
的通项公式;
(2)记
,
,求数列
的前
项和
;
(3)记
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97034664bd213a31e81b9625f83d0e26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4995fa0403e013d888c0935ebfe15024.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd86fd3108963fbf87c75d504fa40cf.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa1093307f363309d7f8d026e9ed0e33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
(3)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b77fb54a6f469a3ee479637e2045d5da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e323e8aff31de40e3574372599fcab.png)
您最近一年使用:0次
3 . 已知
是各项均为正数的等比数列,其前n项和为
,
,且
,
,
成等差数列.
(1)求数列
的通项公式;
(2)设
,求数列
的前
项和
;
(3)设
,
,证明:
.
![](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/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28c40980226328591a49bf85b56b9562.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e02b512e23eadd2810ab21e2e993b712.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3272ce4d31d66c1d408225b997e3a73d.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd2e7b7b013102caae359e4841f8e7a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbd85b79372dc6e596d465f738c3c300.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f275914ae76c22daf8773fc406f0524c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/930bc56406e69b785b37a83d48e36724.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5954dc771c811c8eced9e4c9a19d45ba.png)
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