1 .
这一列是是按规律规律排列的,请问前
个数之和是_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8459493ec2632c04917a859912b8a356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a2ecfa42d53e9a51dd1996aaab957e9.png)
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2024-02-15更新
|
154次组卷
|
2卷引用:第12届“枫叶新希望杯”全国研学营 团体接力赛七升八试题
2 . 观察下列等式:
第1个等式:
;
第2个等式:
;
第3个等式:
;
第4个等式:
;
第5个等式:
;
按照上述规律,解决下列问题:
(1)写出第6个等式:__________________;
(2)写出你猜想的第
个等式(用含
的等式表示),并证明.
第1个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1a774ffee9ff5c6b7ac1971bea80b4e.png)
第2个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d937c354489854bc84961814b1012786.png)
第3个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba3d1f33f69625f3464b3b3c66743c71.png)
第4个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fb59ed262cf0a5febea6827ff655716.png)
第5个等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/343665135b89d18026f06c6b32eb76b7.png)
按照上述规律,解决下列问题:
(1)写出第6个等式:__________________;
(2)写出你猜想的第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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3 . 先观察下列等式,再回答问题:
①
;
②
;
③
;
(1)根据
的规律,直接写出
的值:
_______;
(2)猜想
的值:
_______.
(3)计算
的值.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2eedfd5279481b14c9008cedcfe11dd8.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d1e05ba066831efa619e3e7bb91786b.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db78aca01da568cbb12572dfbd339ad7.png)
(1)根据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e616142cd7122cb7c4e9bc46bb7394.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9246611d5d73aa00eca69b00977a2be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42e4487468ab2823d6dbf7f0ebd2eb38.png)
(2)猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced9bb4b8478a94dd2e4852f2febd771.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3f7fda69e2b32b9ced2239f915fa59b.png)
(3)计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/073a1b61e62680eebdf30c0d05d4b5ec.png)
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4 . 已知整数
,
,
,
,……满足下列条件:
,
,
,
,……依此类推,则
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1bae03ee4ac75dacfb026290e4207dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2add27a9d1cd15c752f27ffd63678286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6bc8a4fadd8f507b12107892e564f5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/876acb6b6cfef62072d9b7588fefab3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f11075f2c574b6c59b97fb3038000e38.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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5 . 观察下列各式:
,
,
,…
.则
的值为______________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e651d23dd38f769a9bffd3d6e4bf5dad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ad1ab457736bf163b7a9a4720e4b92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc7e357507316f2cf8ea76ab66a5e9d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bfaff0dcb48c9ae6c282a84bbd85538.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
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6 . 多个数进行相加时,有许多计算技巧,其中一种为裂项相消法,有一种裂项方法为:当n,i均为正整数时,有
,例如
.根据上述结论,完成问题:
(1)计算:
;
(2)直接写出下式的计算结果:
______;
(3)①计算
的值;
②计算
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a9a024093372deb90015f622ad756b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0000854c31408844913f92c7b71d8cd.png)
(1)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2323b9bf93578ea097aa6bfbaf72e72.png)
(2)直接写出下式的计算结果:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2d44e7938ca380f0ea2b7d943ae73f6.png)
(3)①计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64970ea04cbd945c5c06c30b47962de7.png)
②计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12a8b9de2e0411974844e2d74594056e.png)
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7 . 阅读材料:求
的值.
解:设
,将等式①的两边同乘以2,
得
,
用
得,
,
即
.
即
.
请仿照此法计算:
(1)请直接填写
的值为 ;
(2)求
值;
(3)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc1f74c7107f4a58b533a3f2ba7bf482.png)
解:设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88e012645b1621bdf18f7175b7b703.png)
得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c049af813f7b273bf5e57b44e3b9727.png)
用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa1bc73fa3c38950942a686da4714ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54d420aa3d310379849a31391051c25a.png)
即
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6393d53d188ae527f0caec65312f734.png)
即
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d50e24b468b111aa3c449f3e8aef47c.png)
请仿照此法计算:
(1)请直接填写
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0db5e36fb896dc65c2c3b7d071a8b9d5.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10f9e0c87c398061ad70eecbbc03986b.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e4d573799ab53f1bf9fe5434da25c70.png)
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8 . 观察下面的数据:
,
,
,
,
,
,……寻找规律,第
个数据应是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35361e76a7c85d1886728c8d0200b234.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38387ba1cadfd3dfc4dea4ca9f613cea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b91d650c2fc1a741fabdb333b09aeb6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/810f626d172a0b9aaabebfbeadca97cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6525fb413a15f9d475735f913f8ea98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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9 . 观察下列数据:0,
,
,
,
,
,
,….根据数据排列的规律,第
个数据是__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47153fdd73c0661fa460130082e30929.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35361e76a7c85d1886728c8d0200b234.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81fb134b2b48acc99213fff6ccfee65f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38387ba1cadfd3dfc4dea4ca9f613cea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27c194711803ea093ff6ae78984fc7f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8af2fdf1944afebb51cb6a5e6c74aadd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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2024-01-19更新
|
98次组卷
|
2卷引用:山西省运城市夏县多校2023-2024学年八年级上学期期末数学试题
10 . 已知有理数
,我们把
称为
的差倒数,例如:2的差倒数是
的差倒数是
.如果![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cd0b17809349399d3d5798050778894.png)
是
的差倒数,
是
的差倒数……,以此类推,那么
的值是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c400a615a16a1662de98dfb4e49d58d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99ebf5e8c5ac0fc22e01967fd0c79bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c326c425e9cd49b2ad57872ed8ffcb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30ef59fb25c9976e48dfd03d72699d08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cd0b17809349399d3d5798050778894.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.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/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c510f95f4274d43853e96c594f3159a1.png)
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