已知数列
的首项
,且满足
.
(1)求证:数列
为等比数列;
(2)记数列
的前n项和为
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc6545b8eca1c4223ed701a199a85683.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7643e8b7aa32ebf299048417a94432dc.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/213e22890204937a5dded4436369390f.png)
(2)记数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84a7fd6cdba688a140e8c6f3195acf29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
23-24高二上·陕西西安·阶段练习 查看更多[2]
更新时间:2023-12-10 23:21:18
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解答题-问答题
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适中
(0.65)
【推荐1】在中国绿化基金会的支持下,库布齐沙漠得到有效治理.2017年底沙漠的绿化率已达
,从2018年开始,每年将出现这样的情况,上一年底沙漠面积的
被栽上树改造为绿洲,而同时,上一年底绿洲面积的
又被侵蚀,变为沙漠.
(1)设库布齐沙漠面积为1,由绿洲面积和沙漠面积构成.2017年底绿洲面积为
,经过1年绿洲面积为
,经过n年绿洲面积为
,试用
表示
;
(2)问至少需要经过多少年的努力才能使库布齐沙漠的绿洲面积超过
(年数取整数).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4ec5b9d2f5dbd6ec1cac34dbd8e547.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a026dcb4b3d2c249b1c7193a86657b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/356dd6809a78dacc01ab21226c4afc49.png)
(1)设库布齐沙漠面积为1,由绿洲面积和沙漠面积构成.2017年底绿洲面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87227afdc3af6d6b67bc86a3f611818c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/090426eb29836bc30c006b3739c08057.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/090426eb29836bc30c006b3739c08057.png)
(2)问至少需要经过多少年的努力才能使库布齐沙漠的绿洲面积超过
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/beddb9806191a43e6c6b194300981f11.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】已知数列
的前
项和
满足![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbff64361798257d9696860fddf4c34d.png)
(t为常数,
且
).
(1)求数列
的通项公式;
(2)设
,且数列
为等比数列.
①求
的值;
②若
,求数列
的前
和
.
![](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/cbff64361798257d9696860fddf4c34d.png)
(t为常数,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/823ab696d27d40920c39b8c910789380.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a369ce3949b2bd2747a48054f7b951c4.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98847e799324ba8de0882fe9c3c76a5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
①求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cc4ebe2b1d4531a02b278e08e38c7c1.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)
您最近一年使用:0次
【推荐1】在数列
中,
.
(1)设
,求数列
的通项公式;
(2)求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f224ea87a12e41e153de9760a14bb24.png)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/980d51ba3340a31964fbec9e6f243ca6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求数列
![](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)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】设数列
的前n项和为
,且
,数列
满足
,且
.
(1)证明:数列
是等比数列,数列
是等差数列,并求
,
的通项公式;
(2)设数列
的前n项和为
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28ef6f1b2279af482557a8ea46f2e43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/105738c5cd57c047ba1145c6cb0943e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/195431ccf2756a0db26f14b7b91a32a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d13620d6f9b951b7d6c5964d3b7b7593.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bf620ae89341be941bb58e603ef1859.png)
(1)证明:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28ef6f1b2279af482557a8ea46f2e43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6d84169a989e2461c0d904e93c481ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28ef6f1b2279af482557a8ea46f2e43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/195431ccf2756a0db26f14b7b91a32a7.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9c4bad4ee631eb6ed6798b22f969f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次