1 . 数列极限理论是数学中重要的理论之一,它研究的是数列中数值的变化趋势和性质.数列极限概念作为微积分的基础概念,它的产生与建立对微积分理论的创立有着重要的意义.请认真理解下述3个概念.
概念1:对无穷数列
,称
为数列
的各项和.
概念2:对一个定义域为正整数集的函数
,如果当
趋于正无穷大时,
的值无限趋近于一个常数
,即当
时,
,就说常数
是
的极限值,记为
.如:
,当
时,由反比例函数的性质可知
,即记为
.当
(
为常数)时,
.
概念3:对无穷数列
,其各项和为
,若当
时,
(
为常数),即
,则称该数列的和是收敛的,
为其各项和的极限;若当
时,其各项和
的极限不存在,则称该数列的和是发散的,其各项和的极限不存在.
试根据以上概念,解决下列问题:
(1)在无穷数列
中,
,求数列
的各项和
的极限值;
(2)在数列
中,
,讨论数列
的和是收敛的还是发散的;
(3)在数列
中,
,求证:数列
的和是发散的.
概念1:对无穷数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88c434a9e76de70c0af36c324e1fd48d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
概念2:对一个定义域为正整数集的函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4136968179e01108272af01324034127.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e345e86daf74312a6992e5d1c3f47f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a107eb946e0fe41629c644b7628d5cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6784211a2342d9d829bd95e15b549b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e345e86daf74312a6992e5d1c3f47f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0057f1742dc20e867bcbc29e6475773a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40cd74412213ddb92f6b4637888cf3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a107eb946e0fe41629c644b7628d5cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5cfc53624067d3c8e01f09361295dff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc76422aeaa304648c34cd1c6c0674e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f4eb29a351c1efa18e8e45d083491df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/961ea9a98e63ba37f650fde96c774026.png)
概念3:对无穷数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b06ea1200f943f6eb160b49e584b4335.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a107eb946e0fe41629c644b7628d5cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f614310a33734a2d82f0d84c627028e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2cb2108952d47acb4f0a9518cbef443.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a107eb946e0fe41629c644b7628d5cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b06ea1200f943f6eb160b49e584b4335.png)
试根据以上概念,解决下列问题:
(1)在无穷数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5beb1d3014af78f347ea9cf3661881cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccecde965d7557d5ee35dea8ae7164a3.png)
(2)在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1111d85a7c8b1842e38b5d59da90954.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
(3)在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5ab0309e2cd35585ea9fb2cc3017abf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f34f1354aaa4fa27de5215098e0b1e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5ab0309e2cd35585ea9fb2cc3017abf.png)
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2 . 设
是无穷正项等比数列,公比为
.对于正整数集
的子集
,若
,定义
;若
,定义
.
(1)若
,
,
,求
;
(2)设
.若
、
是
的非空有限子集且
,求证:
;
(3)若对
的任意非空有限子集
、
,只要
,就有
,求公比
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52866a74e4af867ceea0efb1ad06602c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b68df477b3ee45ac0f725db00d465a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2107216f6f7f012fd631c5da84365b86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efbbcfe1c221cbfee862634526d6c1f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e745fd938663191ae254f18b979afc3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c17e4e98aa1080cf1752257a113af45.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58f45f5bc7c648c0e8924b4fa7b1ad08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/799a57bb07e4d32501018027843b7d53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf414809032abdd0d6b259228275757.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4099a6a331e90aa8b7fdd3c113673896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52866a74e4af867ceea0efb1ad06602c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dea9a4259cca10c1f5af28e621ebafd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16d65b558a0445c59c83fa28d9ca0f37.png)
(3)若对
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52866a74e4af867ceea0efb1ad06602c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3675d10cb915e25bf349649b2e20e08d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cfaafb17097504a9bdd0317a0ecabe5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
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名校
3 . 设数列
的各项都是正数,若对于任意的正整数
,存在
,使得
、
、
成等比数列,则称函数
为“
型”数列.
(1)若
是“
型”数列,且
,
,求
的值;
(2)若
是“
型”数列,且
,
,求
的前
项和
;
(3)若
既是“
型”数列,又是“
型”数列,求证:数列
是等比数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cad52924df9291d5d191d18e09374ee1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/681ae1522a36768618f7ddaf74abbb7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93ab544636f4e8a933f88e4fdd5a0f17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/453cd35e55fefbedb6210c2cca7fabcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63666ed9a7dfd5b578b43d513468acff.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10a27ee67f4016a48492a614ea2dc774.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2761c9ee8b440dd678baee4c17fdada.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c296e45b84cf67a98939aa7334e7d478.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1e1cbde26dc8fc0139bf9b917303fb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f1e55cb07aa8350755e0e4f54ca0fe3.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/08eb71ecf8d733b6932f4680874dbbf3.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c296e45b84cf67a98939aa7334e7d478.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de8ce8c07e34224e2d25130ed27c9a98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
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2019-08-17更新
|
462次组卷
|
2卷引用:上海市格致中学2018-2019学年高三下学期三模数学试题
名校
4 . 已知:函数
,数列
对
,总有
;
(1)求
的通项公式;
(2)设
是数列
的前
项和,且
,求
的取值范围;
(3)若数列
满足:①
为
的子数列(即
中每一项都是
的项,且按在
中的顺序排列);②
为无穷等比数列,它的各项和为
,这样的数列是否存在?若存在,求出所有符合条件的数列
.写出它的通项公式,并证明你的结论;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910617443037769340f252e4efe21536.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ea88016f672b8f54901e457cceecca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d500d7b62f418a4bcd75ce718c8c5a7.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4373b0bead6e6acdd697c6693e7d4af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
(3)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41cf1da18d91f7c98086553d157d1a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41cf1da18d91f7c98086553d157d1a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41cf1da18d91f7c98086553d157d1a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
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真题
5 . 设数列
满足
为实数
(Ⅰ)证明:
对任意
成立的充分必要条件是
;
(Ⅱ)设
,证明:
;
(Ⅲ)设
,证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aeed162eb09f2bef04ee28ecc13b59c3.png)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/904ab7f5bce6ec587851151bc9c4787a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d726666f99a5a41dd673a2330e377b17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5a6916a4386d6941683f9e47abde0e6.png)
(Ⅱ)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf770a8cbbaa535345e92820098269b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f16388f80cfa5da7c13e8907a6d09b4.png)
(Ⅲ)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf770a8cbbaa535345e92820098269b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d44b49a03d86c94d5575374aff056d7a.png)
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