我们将
与
称为一对“对偶式”.可以应用“对偶式”求解根式方程.比如小明在解方程
时,采用了如下方法:
,又因为
①,所以
②,
由①+②可得
,
将
两边平方解得
,代入原方程检验可得
是原方程的解.
请根据上述材料回答下面的问题:
(1)若
的对偶式为n,则
_______;(直接写出结果)
(2)解方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a989c4fbf0ff34cedb365d2dda47f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/175d0c99e866f1db915462a91b356ef3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7e95857b9fcde7b45e59ef3d498e456.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45df46a4c4a7238fc3139f9d8f760425.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7e95857b9fcde7b45e59ef3d498e456.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7f70738cc5d8a4c4bbcbae8063ade58.png)
由①+②可得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/219e7aa832d6637d8cd51c1cb1ecf2f2.png)
将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/219e7aa832d6637d8cd51c1cb1ecf2f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99c6875d552e9fff3c7d655f3a59b166.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99c6875d552e9fff3c7d655f3a59b166.png)
请根据上述材料回答下面的问题:
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c06c3ffaefef93e5ba33cb18cac0a7ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afdc55dd0ece95a801b1d35821583a37.png)
(2)解方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e0fd1e84e7b41f350317a28c4cb6de1.png)
22-23八年级下·江苏盐城·阶段练习 查看更多[2]
江苏省盐城市亭湖区盐城景山中学2022-2023学年八年级下学期第二次课堂检测数学试题(已下线)第20讲 二次根式的加减(3大考点+11种题型+强化训练)-【帮课堂】2023-2024学年八年级数学下册同步学与练(苏科版)
更新时间:2023-08-16 20:31:23
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解答题-问答题
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解题方法
【推荐1】观察下列各式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77fc530917ade098f3a481f1ada4bd8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c97f3e0b3eb6ad36aaba9e6c3c6bbe9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfdc088d5384f01280e91e9b5964a40c.png)
(1)根据以上规律,则
___________;
(2)你能否由此归纳出一般规律
___________;
(3)根据以上规律求
…+
的结果.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77fc530917ade098f3a481f1ada4bd8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c97f3e0b3eb6ad36aaba9e6c3c6bbe9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfdc088d5384f01280e91e9b5964a40c.png)
(1)根据以上规律,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee3d3b6a490d7062648edcb8d6076f44.png)
(2)你能否由此归纳出一般规律
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f73578c5c9b287487a09a1100ec9916e.png)
(3)根据以上规律求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02ba9467f3819a1bd6038ebeb25d9a80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3595cb9bb9e185b75f8cc88ae673ce.png)
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解答题-计算题
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【推荐2】(1)计算:
___________________;
___________________;
___________________;
(2)利用上式的规律,求:
____________________;
(3)已知
,请分别求出
和
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bf44d48be3e1c695124276d2df80de1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8dfc77624c0c3783fcc5068e43e850a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c70dd7943256377ecaf3c7e031a12321.png)
(2)利用上式的规律,求:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8345caee7e49a6c587af6d97893efb1.png)
(3)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb9114da3da9e0680fe39bf86eab63e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fc08021643d542f3d579352a9d00ff8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/799c8cb4e9ecbf4c8007b6c08f2a3d8a.png)
您最近一年使用:0次