如图所示的三角形表,最早出现在我国南宋数学家杨辉在
年所著的《详解九章算法》一书中,我们称之为“杨辉三角”.若等比数列
的首项是1,公比是
,将杨辉三角的第
行的第1个数乘以
,第2个数乘以
,……,第
个数乘以
后,这一行的所有数字之和记作
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/f1cb3d9d-59ce-41f0-8292-3c8d372ebbf3.png?resizew=332)
(1)求
的值;
(2)当
时,求
展开式中含x项的系数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fa99a11fa9079e92173593420f2715f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe229b24e2d56ff6b491725ceae4ff2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0575508fcd0f7974232dfb5534c3251e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66330dafc483dacc8b795cbc2d7c1f44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b42791b77924729f7e31712177b26af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cb5ca241bb7c313ef0366d3ddba93bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66330dafc483dacc8b795cbc2d7c1f44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7085d141e33ba0188e58fa2177d89ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/357708368acb586366a77ec9c3c32e88.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/f1cb3d9d-59ce-41f0-8292-3c8d372ebbf3.png?resizew=332)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d517ae63082bebf6d2bb9f8427d50f1d.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66d188de05701eabcb9544f48350877e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e5aae57f153407391de15607bb0751f.png)
更新时间:2019-03-27 21:19:40
|
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】在①
展开式的各项系数之和为
,②
展开式中各项的二项式系数之和为512, 这两个条件中任选一个,填在下面的横线上,并解答.
已知_______,求
展开式中的常数项.
注:若分别选择两个条件作答,按第一个作答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4040ff8d95b6f4f5c4584f5f30e6224b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10386ff769207c4dc07ec2634d063526.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4040ff8d95b6f4f5c4584f5f30e6224b.png)
已知_______,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3350398f6593dd81019fdcbd497cc73e.png)
注:若分别选择两个条件作答,按第一个作答计分.
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解答题-问答题
|
适中
(0.65)
名校
【推荐1】在平面直角坐标系
中,有一个微型智能机器人(大小不计)只能沿着坐标轴的正方向或负方向行进,且每一步只能行进1个单位长度,例如:该机器人在点
处时,下一步可行进到
、
、
、
这四个点中的任一位置.记该机器人从坐标原点
出发、行进
步后落在
轴上的不同走法的种数为
.
(1)分别求
、
、
的值;
(2)求
的表达式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d7a999c36de5c9a9ce876a4a56fa34c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fab8a0cc6504aa4c3a38006f5394b4c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b2c84e7b41a841a230ed5f8a42309aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6caada92ccee5634fe08350c7a3f4d99.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d0924ff22fff9f5639feb0ceeece80d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2837f8a4d91ca4202f69e39abf3f603.png)
(1)分别求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4c8381377b90826897eb4bf16cb3bae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4bf72626042d976d413196215876684.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098bc5afd71a3fecf92895efa25e7c06.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2837f8a4d91ca4202f69e39abf3f603.png)
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解答题-证明题
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适中
(0.65)
【推荐2】设![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c30ee388d945875e585c25daec7e2fc4.png)
.
(1)若
,求证:
是完全平方数;
(2)证明:存在无穷多个正整数对
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.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c30ee388d945875e585c25daec7e2fc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f82b872914335d22f93f6c866d2b5c61.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58b2fb1017d5dfe3a300de3e14a71b6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43f41be870e84c819362787849770519.png)
(2)证明:存在无穷多个正整数对
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/698c4d4e50062b4a7dd70fe1b4ab4fd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58b2fb1017d5dfe3a300de3e14a71b6f.png)
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