1 . 已知
为等差数列,
为各项均为正数的等比数列,
.
(1)求
和
的通项公式;
(2)求
的前
项和;
(3)若对任意
,有
恒成立,求实数
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68c441d153bb85e08d02f079496125f4.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec8b68d90e55b00b6662a23f851cca89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(3)若对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17bd8c5d3cc62cb0d57249d00a585fed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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解题方法
2 . 设
为无穷数列,记
,其中
为常数且
.给出下列四个结论:
①若
,则
为单调递增数列;
②若
,则
为单调递减数列;
③若
,则对任意
且
均存在最大项;
④若
,则对任意
且
均存在最小项.
其中所有正确结论的序号是____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c464e05e8f4af798857922acee1b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b06a27bb553c7d73ac3b4ab67ff4bddd.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d48054d9bd5e864044fbf3192fd869a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21c122d09c11612333aeddd247399582.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/677e46ecd051c92489c0d1d458932f37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/544530e1133b2924ccfbe691141a5641.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7d1d4a3e830beaa5a649316adba00fa.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/677e46ecd051c92489c0d1d458932f37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/544530e1133b2924ccfbe691141a5641.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7d1d4a3e830beaa5a649316adba00fa.png)
其中所有正确结论的序号是
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解题方法
3 . 设等差数列
的公差为
,前
项和为
,已知
.
(1)若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
___________ ;
(2)若
,则
的最小值为___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.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/630df1e98d73e9c43bd8378991534dd6.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a749d8f7bbec9b1c624c0bb254247a6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae3012337aa392709349731fb1eef5b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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4 . 已知等比数列
中,
,则
的公比为___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/130bc25db855292f7383a59eeb9107a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
您最近一年使用:0次
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5 . 已知数列
满足:
.若
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8ca5386f255077298d507e6aa6c1f46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e076d53e0fab96afda46ff7ac1689dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42e4487468ab2823d6dbf7f0ebd2eb38.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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6 . 已知
均为等比数列,则下列各项中不一定为等比数列的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e567d7e9761951a266953c8d5042ac.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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7 . 已知数列
的前
项和
,则
( )
![](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/f83df6bf0e6127d2df3141888c088249.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbfc875ca919921e8f63a6fca648561b.png)
A.16 | B.32 | C.48 | D.64 |
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8 . 已知等差数列
中,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1463b2a02b06a88cc34f6e3535b3867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
A.8 | B.9 | C.12 | D.18 |
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9 . 解关于
的不等式.
(1)
;
(2)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98095d33453ef6422a146e1624eadcdd.png)
(3)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/594bdf0580b5ee955ed575bf3024cbaf.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98095d33453ef6422a146e1624eadcdd.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d856e444f17096e1efc1f4524e42fb1e.png)
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10 . 对于任意实数
,
,
,
,命题 ①若
,
,则
;②若
,则
;③若
,则
;④若
,则
;⑤若
,
,则
.
其中真命题的个数是 ( )
![](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/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fef20073a12bab727faa217718b63414.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b34c5832f3fe28f48a924854cb8814ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c22b9d08cf536bbb76bce1b0f135772.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c22b9d08cf536bbb76bce1b0f135772.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cb54b1b3617ebc502cb44194cbcd1dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a0c4c098615c6bc7e6dcf72e5b5201a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44cbc322861846709c08c7f1da746848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27f50ce6b511e6b928796e048fc7fa5c.png)
其中真命题的个数是 ( )
A.1 | B.2 | C.3 | D.4 |
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