(1)计算:
.
(2)化简并求值:
,其中x、y取值的位置如图所示.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74ddcbf9b144f8ba343907513af7394b.png)
(2)化简并求值:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed9c7bff7cc4388afc44a7f9ffd89cd6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/8/a58a8c9c-303e-46a4-ba8d-741cde1ee4a7.png?resizew=243)
更新时间:2022-01-17 15:58:48
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解答题-问答题
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【推荐1】(1)找规律:1,2,4,8……,则第n个数为________.
(2)求和
,观察发现,从第2个加数起每一个加数都是前一个加数的2倍.于是可假设:
①
两边乘以2得:
②
②-①得:
,所以:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceb6ae124e42bf7d9f1ae189d1cf9116.png)
类比做一做,求
的值.
(3)仿照(2)的做法求
的值.
(2)求和
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b739bd89abf31a4895b4277d3aa6b998.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df5c6a3fee73554e1db9ef2e99b4ca29.png)
两边乘以2得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/973d3b8426714942b40d050b7e58bf5a.png)
②-①得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae18195d0b21f258d37dea37bde03560.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceb6ae124e42bf7d9f1ae189d1cf9116.png)
类比做一做,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2c4488fe7fb486d7198ba654166e7a.png)
(3)仿照(2)的做法求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b7e28cc19e29cad21e3194b26fbfa1d.png)
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解答题-计算题
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适中
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【推荐2】计算:
(1)计算
,根据提示完成计算,并补全相应步骤的运算依据.
解:原式![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c86f69e593c3a7a94996d8a209e2de6.png)
运算依据:加法__________律;
运算依据:加法__________律;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eb308b3cde04a65f341b9f7d7614fff.png)
__________;
法则:绝对值不相等的异号两数相加,和取_________的符号,并用____________.
(2)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e74827cfac31bea47b46d3f669ba2600.png)
(3)
.
(1)计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/027c947d3bc558f6c602727bf4f9d66a.png)
解:原式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c86f69e593c3a7a94996d8a209e2de6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9190b80b53c2253680c290971c99a927.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f40ed55bcdad72d005797bb29e2b57fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eb308b3cde04a65f341b9f7d7614fff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6706fe00b4e231e62d9ecbec567d526b.png)
法则:绝对值不相等的异号两数相加,和取_________的符号,并用____________.
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e74827cfac31bea47b46d3f669ba2600.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2faffcf2f9d1be88a962099d154711c6.png)
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解答题-计算题
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适中
(0.65)
【推荐1】(1)计算:
;
(2)计算:
;
(3)计算:
;
(4)先化简,再求值:
,其中
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/468d0dc2e05fc77c65c0fdadc848ce5e.png)
(2)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/637bcacdf5aad72e791ea76e03e0f3c3.png)
(3)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987b3d64bd3223f149a95dc111100d1c.png)
(4)先化简,再求值:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6ef1773294e5db848e0d1342f4d09cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dee0636bd0d7bdff2e14027ce41be4c.png)
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解答题-问答题
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【推荐2】已知关于x,y的多项式
与多项式
的差与字母x的取值无关.
(1)求a,b的值;
(2)求代数式:
的值;
(3)求:
…
的值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aee4d6f605b3fa5319795761a6cfa9b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb10d871875f0568f81d4e63eaaf9a25.png)
(1)求a,b的值;
(2)求代数式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235c1501e5efd43d8ca981574b92321a.png)
(3)求:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41768111d1442c4f7a10bfdd65df5c53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a8c08c390c39dfa4665fdbf6b58be80.png)
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