1 . 求下列各组数的等比中项:
(1)
和
;
(2)
和
;
(3)
和
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e47e81a68121fad598f1e8be775d458.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6be6e514c2de895c26e09c6de76ad4d0.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/025522dcece5957f1fe3a41de5c93ddf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d266a1b19b18649d8691b884123d33c8.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/118933cede78675413dbafac24ee008c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/897aeafa8da0737baa70f64fdf55c269.png)
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2023-10-11更新
|
381次组卷
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2卷引用:北师大版(2019)选择性必修第二册课本习题第一章3.1 等比数列的概念及其通项公式
23-24高二上·全国·课后作业
解题方法
2 . 已知数列
为等比数列,k是小于n的正整数,
是
和
的等比中项吗?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ab5b3fb212ed2113ff5410a40068cbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4624141790a9fddfb8be85592ccf3e1f.png)
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23-24高二上·全国·课后作业
3 . 求出下列等比数列中的未知项:
(1)3,a,27;
(2)
,a,b,
.
(1)3,a,27;
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3389f53711264b0acba3ba6019f8b908.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b8d1ca7682da10dc7f36e858593d51f.png)
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21-22高二·江苏·课后作业
4 . 已知等差数列
的公差d不为0,若
,
,
成等比数列,则
的值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fd71bc7e6668f90f259ad0b06dd60c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e151e8083936ff799a0f27c54704d9.png)
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21-22高二·江苏·课后作业
5 . 三个数成等比数列,它们的积等于8,它们的和等于-3,求这三个数.
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