观察下列等式:
第1个等式:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f22524595a3d43d081d767909d442244.png)
第2个等式:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94a4204dccc48346201c0a41c0eebad9.png)
第3个等式:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0364ed858a3be93fa45029f8686131a8.png)
第4个等式:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ab108e37fb6db079bc70b8549459c05.png)
……
请回答下列问题:
(1)按照上述规律,写出第5个等式:
;
(2)用含
的式子表示第
个等式:
;
(3)求
的值.
第1个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f22524595a3d43d081d767909d442244.png)
第2个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94a4204dccc48346201c0a41c0eebad9.png)
第3个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0364ed858a3be93fa45029f8686131a8.png)
第4个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ab108e37fb6db079bc70b8549459c05.png)
……
请回答下列问题:
(1)按照上述规律,写出第5个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6706fe00b4e231e62d9ecbec567d526b.png)
(2)用含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6706fe00b4e231e62d9ecbec567d526b.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e0d7db0206fce4ec13d994011a6b480.png)
更新时间:2020-04-07 11:55:58
|
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解答题-问答题
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适中
(0.65)
【推荐1】观察下面三行数:
,1,
,4,
,…;①
1,1,2,3,5,8,…;②
2,
,8,
,
,…;③
(1)第①行数的第2023项是:________.
(2)第②行数的第10项是:_______.
(3)第③行数的第20项是:_______,第n项是:_______.[(3)两空均用幂的形式表示]
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/529709040fa0a98ce729428f6cec8db8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274a9dc37509f01c2606fb3086a46f4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bf3d3564c61e5e9c39a9e2cf2de048b.png)
1,1,2,3,5,8,…;②
2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3edbd40e04e2a943051fa83d6e511add.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec54f53122364c46e1e43d1a84f210fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/332e71982612ea86c28b9f2054b1045c.png)
(1)第①行数的第2023项是:________.
(2)第②行数的第10项是:_______.
(3)第③行数的第20项是:_______,第n项是:_______.[(3)两空均用幂的形式表示]
您最近一年使用:0次
解答题-计算题
|
适中
(0.65)
名校
【推荐2】(1)观察一列数1,3,9,27,81,…,发现从第二项开始,每一项与前一项之比是一个常数,这个常数是_____________;根据此规律,如果
(
为正整数)表示这个数列的第
项,那么
______________,
______________.
(2)为了求
的值,可令
,则
,因此
,所以
,即
.
仿照以上推理,计算
请写出计算过程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9e61cea2dd2e030616c36bbcd2c8b49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
(2)为了求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0f0883a31c6f4ac280f849db5c9e2e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8334f2a3eebab2fd6315ee4bcc8c8af1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7253dc5f3f28176349159dc5e63dd4dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5694c5ab178d54572ebb443f1a51f9b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3e1f66f79021fc58b6bf656f779cf22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50cb756e0f16a95c09d0a8c134a04144.png)
仿照以上推理,计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b764f96aa76bb1e31b2ae3cf4002e7e4.png)
您最近一年使用:0次