设
是公比大于1的等比数列,
为数列
的前n项和.已知
,且
是
和
的等差中项.
(1)求数列
的通项公式;
(2)设
,数列
的前n项和为
,求证:
.
![](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/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ccdc17b603871d20843ffccca2df0ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/911278aa8595846abac1972e1de59995.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7131900393b9906bd6dcfe26ade2059f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0462c9dc4a0bd08a0ec1cc07f1d2f3e6.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36925e53ab12172c7616b6d64b608b16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9928e46511e601913619a427ded84a3.png)
更新时间:2020-01-04 16:37:18
|
相似题推荐
【推荐1】已知
前n项和分别记为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c6a39c60c21953936c069945f659203.png)
(1)若
都是等差数列,且满足
求
;
(2)若
是等比数列,
是等差数列,
求![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f550f4135c46fbfb0c001e662cd8ff6.png)
(3)数列
都是等比数列,且满足n≤3时,
若符合条件的数列
唯一,则在数列
、
中是否存在相等的项,即
若存在请找出所有对应相等的项,若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a817a5a9aa44e7610becef6f8f4960bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c6a39c60c21953936c069945f659203.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942ed174dfdafaf5f0a68cac579110f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd5af730344e87d1c9344824468b20db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d16765bfe96c4c2733afdf4099a33f5e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f9abea51fe3e27c88aab5a6d9c1f655.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f550f4135c46fbfb0c001e662cd8ff6.png)
(3)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942ed174dfdafaf5f0a68cac579110f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dea72c3a63462c67b1d9e3c99c16aeb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94909140d2fac93cfe453499ccb22e74.png)
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】记
为等比数列
的前
项的和,且
为递增数列.已知
,
.
(1)求数列
的通项公式;
(2)设
,求数列
的前
项之和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18d8e8f821111de8075e5c3dfb22a5d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/964df3e9308711d7e14fb624b0c25e2f.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab89ad51d15859efe9c3444d2677b37d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次
解答题
|
适中
(0.65)
【推荐1】已知数列
的首项为
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7abb82ff6aed22a0d3540cac0a0ca80.png)
.
(Ⅰ)求数列
的通项公式;
(Ⅱ)若
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7abb82ff6aed22a0d3540cac0a0ca80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5e07bf129b073f37b553fbca100172.png)
(Ⅰ)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3952eb2e8c0e1315ba185d7bc4b484e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da72309d2507e2f5e5ed88d8cc08963.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次
【推荐2】已知数列
满足:
,且
.记数列
为
,记数列
为
.
(1)求证:
是等差数列,并求
的通项公式;
(2)记
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7570ea38d8c1d1a26d5af1d92fc9528b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86fc336b4a83bf6d66c4afcc431597f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c720caa66edcd6a2631bc7aa7b2e4b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/806bf80ed963c7f3c46a1e7e1e928169.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5013fe04a70b626035a6fa921dd8469.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b783cf91e34e692ce8e171f0965cb53f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次