1 . 已知正项等差数列
与等比数列
满足
,
,且
既是
和
的等差中项,又是其等比中项.
(1)求数列
和
的通项公式;
(2)记
,其中
,求数列
的前2n项和
;
(3)令
,求证
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eab7d59ce066c8f0b346719003f8e28f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea74a5cf39bd1149aed1ce6c8ba0c895.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/161a7b35d1812e6745ae7f7c540cf87a.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/48ab19d5a8c560c50f98d3c740cdcce5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cad52924df9291d5d191d18e09374ee1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b9a0d7150fb24be3e28ef7f0e18be93.png)
(3)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf2443287aedee2d3385a27b101cbfd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89e491daeb7795dcdf667cdef82a0200.png)
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2022-04-29更新
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3卷引用:天津市滨海新区塘沽第一中学2022届高三下学期4月统练数学试题