已知数列
中,
,前
项的和为
,且满足数列
是公差为
的等差数列.
(1)求数列
的通项公式;
(2)若
恒成立,求
的取值范围.
![](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/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a31c33279d82bc509aa921e2b0c03da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afd7c1d80f49f7aeca1ab29e0e0d26fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
更新时间:2019-09-29 11:10:27
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相似题推荐
解答题-问答题
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解题方法
【推荐1】已知等差数列
与等比数列
满足
,
.
(1)求数列
和
的通项公式;
(2)若数列
的各项均为正数,记数列
的前n项和为
,数列
的前n项和为
,比较
与
的大小.
![](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/7c5a7a17a394e868e0acd1803a9ab795.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b684f9a0e4e928c89df1deaf57b3a5c.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](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/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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【推荐2】若数列bn=
,如果对任意的n∈N*,都有
+bn≤t2恒成立,求实数t的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab630490058b16ccddb216a4e3c7ee56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/357821e0e5595eaf3028df63d47b2c58.png)
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【推荐3】某市旅游局为尽快恢复受疫情影响的旅游业,准备在本市的景区推出旅游一卡通(年卡).为了更科学的制定一卡通的有关条例,市旅游局随机调查了2019年到本市景区旅游的1000个游客的年旅游消费支出(单位:百元),并制成如图频率分布直方图:由频率分布直方图,可近似地认为到本市景区旅游的游客,其旅游消费支出服从正态分布
.现依次抽取
个游客,假设每个游客的旅游消费支出相互独立,记事件
表示“连续3人的旅游消费支出超出
”.若
表示
的概率,
,
,
为常数),且
.
(1)求
,
及
,
;
(2)判断并证明数列
从第三项起的单调性,试用概率统计知识解释其实际意义.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29bcc248a7770a16fa10fc4602d71e0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1100379a4385b9ce064847bc21760adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf83e20035c3afd6d26ebfd53d768a70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce9297cd87607255b5c2258b00d43c70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0eb0e161152d3f8993324e2ebbeb85a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83152b2c2aa879fa7e515f7d4fd574b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/11/1518dcbe-855e-406d-bd1e-381e64d5210d.png?resizew=233)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/797e67927616b141ed7c6b83f8b6f4fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fee50575e3ebd56c4f46dd0bbf8e55d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
(2)判断并证明数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a053773b4287e5e9bfefd693c826237f.png)
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【推荐1】对于正数
,我们称
为它们的调和平均数,已知数列
的通项公式为
,且数列
的第
项
是数列
的前
项的调和平均数.
(1)试求数列
的通项公式;
(2)求出数列
中数值最大的项和数值最小的项.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a7a93362dd500525dfeca6d9a59bbea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc2ccc84d858398653d0e6f0802c73ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23c0c2ae17f859a3fb0ef1a2a967bb3.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/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(1)试求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求出数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7f78d6f36cb572dc4bbcb0d8f53a4c3.png)
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【推荐2】已知数列
的前
项和为
,且满足:,
,
(1)、求数列
的前
项和为
;
(2)、若不等式
恒成立,求实数
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b708c8dcb2d66eb2ce0b3718a9cd924a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a50f6540bb22c82ef6f960b0cebd408.png)
(1)、求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b708c8dcb2d66eb2ce0b3718a9cd924a.png)
(2)、若不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc8b62743b968571006649c50eedc274.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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【推荐1】设等差数列
的前
项和为
且
.
(1)求数列
的通项公式及前
项和公式;
(2)设数列
的通项公式为
,问: 是否存在正整数t,使得![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33e509f6edbcf0a7ba0e50c268d3c0e7.png)
成等差数列?若存在,求出t和m的值;若不存在,请说明理由.
![](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/117464f527849ab995858aaa20f4175b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ee36dfbe9491140d708b820c4c283f0.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2189fce54ebdf5321132b3a181fe92f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33e509f6edbcf0a7ba0e50c268d3c0e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1147eab7e2725a3b7aeee7d6c84e4ed.png)
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【推荐2】已知数列
满足:
,且
.
(1)求证:
是等差数列,并求
的通项公式;
(2)是否存在正整数m,使得
,若存在,求出m的值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50ada5be4490611aae7f00f5e5988bd2.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a44cfbb86a4eb76261c00ddc6bff181.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
(2)是否存在正整数m,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55fddf20dbe45c34efef5b2c3a709c0b.png)
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【推荐1】给定三个条件:①
,
,
成等比数列,②
,③
,从上述三个条件中,任选一个补充在下面的问题中,并加以解答.
问题:设公差不为零的等差数列
的前
项和为
,且
______.
(1)求数列
的通项;
(2)若
,数列
的前
项和
,求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7da2f386b78cdf6489efaa2f5820d3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f9b2392bd67dc2427bf0654ec0d7857.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0936c79a51e0e1f504ff65f98adf9131.png)
问题:设公差不为零的等差数列
![](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)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1dfe5b322577f02fd19caab8cf20170.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf62e018d5136fd80adbd20808bcf0e5.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/aae6358af7332d7609bf8d18467487d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aae6358af7332d7609bf8d18467487d3.png)
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【推荐2】在①
,②
这两个条件中任选一个,补充在下面的问题中,并解答.问题:在等差数列
中
,且
,9,
成等比数列.
(1)求
的通项公式.
(2)设 ,数列
的前n项和为
.若选择条件①,求使
成立的n的最小值;若选择条件②,求使
成立的n的最小值.(注:如果选择多个条件分别解答,按第一个解答计分)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0af85bec1dce52b3e682cfbe4f152fbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13a6e1d671215fc96e4bee3541d1096.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eca7e7b23fd74e3cf89ac541cb7a5d88.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设 ,数列
![](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/cfd912be9a0a0ed34fa7af74d17faf57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3b03471dfec00c2ec9df34370ed677f.png)
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