观察下列有规律的数:
,
,
,
,
,
…根据规律可知:
(1)第8个数是 ;
(2)
是第 个数;
(3)计算:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cfa1e7ffae662aefb49a44c52d4954d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b624e6d456c5aa077dfd00ada3a311d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d7abf02717d6e59d8a64a65a87c412.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba8930e9a26a52a6b09740c1dddbd40e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee2196a9fdcef8d0874487c5f85fdb40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/543c342022938a3bc0366498c07b6778.png)
(1)第8个数是 ;
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4407b50237e63c2f0af68f7710e63856.png)
(3)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8cfb1ce83ddb1ad0926bbb1243767f8.png)
更新时间:2023-11-04 14:38:39
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【推荐2】已知
均为有理数,按要求解答下列问题:
(1)已知
,
互为相反数,
,
互为倒数,则
,
;
(2)在(1)的条件下,若
是最大的负整数,
与
互为相反数,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c970b862bcb1ff80f9917ea4fa3c77b.png)
(1)已知
![](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/892560dcff6af9f66a3f735652f69dd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f56c7629163c5fe76b2c5990d7ac1f4.png)
(2)在(1)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acbc6a613224461ade69362d46550474.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d8de3f1cd7bcca2d492969efbb7fb4b.png)
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解答题-计算题
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【推荐1】阅读下列材料,然后解答问题:
,
,
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aee7bb49247387a9028602315729f8d7.png)
;
;
;![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aee7bb49247387a9028602315729f8d7.png)
解答下面的问题:
(1)猜想:1+2+3+……+n=______;
(2)计算:
.
(3)拓展应用:计算:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0375eced4261cc975a7ebce15d9ef7e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88bfb492b77971528b2fac14d09f28c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7882c63811154e18558ae8729f5b09c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aee7bb49247387a9028602315729f8d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d842b2e150d723c948234ee36f4b6b0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b61dfa259a7cfab28fe63ff7d6211b1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7f4890678dc22224b4d23a8c38fbf11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aee7bb49247387a9028602315729f8d7.png)
解答下面的问题:
(1)猜想:1+2+3+……+n=______;
(2)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4873cb37c0e8e283939c283677cf4b0c.png)
(3)拓展应用:计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25e701915cf889bf89cb4c57a1ca1160.png)
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【推荐2】我国著名数学家华罗庚先生说过:“数形结合百般好,隔裂分家万事休”,数形结合的思想方法是数学学习中的重要思想方法之一.
【提出问题】
,……是一些十位数字相同,且个位数字之和是10的两个两位数相乘的算式,是否可以找到一种速算方法?
【几何建模】用长方形的面积表示两个正数的乘积,以
为例:
步骤1:画长为47,宽为43的长方形,如图一,将这个
的长方形从右边切下长40,宽3的一条,拼接到原矩形的上面.
步骤2:几何建模步骤:原矩形面积可以有两种不同的表达方式,
的长方形面积或
的长方形与右上角
的长方形面积之和.
即
①
. ②
请你参照上述几何建模步骤解决问题:
(1)根据图二所示,结合①与②,完成填空:
;
(2)通过模仿图一与图二,请画出
图形表示,再计算
的值;
(3)总结规律:若
都是两位数,且他们的十位都是
的个位是
的个位是
,根据以上规律写出
的代数式结果.(不用化简)
【提出问题】
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba25346fae3faf8891fa2cb3c56ea109.png)
【几何建模】用长方形的面积表示两个正数的乘积,以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13c77a6cbdbe306f8494385e4962ab51.png)
步骤1:画长为47,宽为43的长方形,如图一,将这个
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13c77a6cbdbe306f8494385e4962ab51.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/27/116c1c96-1d13-478c-a8aa-c97964cad1a4.png?resizew=339)
步骤2:几何建模步骤:原矩形面积可以有两种不同的表达方式,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13c77a6cbdbe306f8494385e4962ab51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8b5ca932acc50b7676071d4c7110dd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c67ba61fb0439192e43cb7c05d46fb9f.png)
即
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a6ba253fbefea42fa54a65de7b6dce6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289fbf3a8af9b76a6e8000da593abb36.png)
请你参照上述几何建模步骤解决问题:
(1)根据图二所示,结合①与②,完成填空:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0227d6ee1c13b200dba04ef962b28a4.png)
(2)通过模仿图一与图二,请画出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/704c70a5de8e5f864f0f2d713369e506.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/704c70a5de8e5f864f0f2d713369e506.png)
(3)总结规律:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e52586ca2a3b783bc8092415e2d4bf6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b87436ec77a13eefd9e8a0865a6c1cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7efbbcbcad9de527409a6609c6a10def.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8df69c6a544f62a016490b012c353ae7.png)
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