名校
解题方法
1 . 数列
满足:对一切
,有
,其中
是与
无关的常数,称数列上有界(有上界),并称
是它的一个上界,对一切
,有
,其中
是与
无关的常数,称数列下有界(有下界),并称
是它的一个下界.一个数列既有上界又有下界,则称为有界数列,常值数列是一个特殊的有界数列.设
,数列
满足
,
,
.
(1)若数列
为常数列,试求实数
、
满足的等式关系,并求出实数
的取值范围;
(2)下面四个选项,对一切实数
,恒正确的是.(写出所有正确选项,不需要证明其正确,但需要简单说明一下为什么不选余下几个)
A. 当
时,
B. 当
时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83ebf3d559b3ccf4427a9464dc9dbd4.png)
C. 当
时,
D. 当
时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83ebf3d559b3ccf4427a9464dc9dbd4.png)
(3)若
,
,且数列
是有界数列,求
的值及
的取值范围.
![](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/5612ce06759d0f77ca029d10083f7d1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63cad0f23354aa754ade482d849557fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/773ca22fc12ade9e60dbc749ba5cfa73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7fab51121848ce166035ceab6f4e00b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73702a22abbf58a70e56a40540de7355.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
(1)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.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/2c94bb12cee76221e13f9ef955b0aab1.png)
(2)下面四个选项,对一切实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
A. 当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87bd9f5db8b97abf9bdd15b8efb6c64d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83ebf3d559b3ccf4427a9464dc9dbd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc64eaf4cd6737b000b28f1fcdd16c4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83ebf3d559b3ccf4427a9464dc9dbd4.png)
C. 当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f06408895febc126c2ae409e807349c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83ebf3d559b3ccf4427a9464dc9dbd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cca0ec4b4343a6ccd13b652aea1d00c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83ebf3d559b3ccf4427a9464dc9dbd4.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1e69392d21261afd8e5e5f096634669.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbb6f7b71775c568314728843894813e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
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