北邮英语
一、单项选择题（共10道小题，共100.0分）
1. What shall I do to ________ this _________ getting dirty?
A. from…keeping
B. keep…from
C. keeping…from
D. keep…on
2. She felt __________ and did nothing but sleep the whole day.
A. slack
B. the slack
C. slacking
D. slackly
3. Mary _________ with embarrassment when she couldn’t answer the question.
A. shivered
B. worried
C. flushed
D. scattered
4. The birds __________ at the sound of the gun.
A. spread
B. scattered
C. flied
D. sped
5. Aunt Mary gave us sandwiches for our picnic and a bag of cookies in __________.
A. address
B. addition
C. a way
D. fine
6. (错误)
The letter was __________ in its wording.
A. former
B. formula
C. form
D. formal
7. (错误)
There isn’t much__________ between their view and ours.
A. comment
B. committee
C. correspondence
D. corridor
8. I would _________ play tennis than football.
A. quite
B. simply
C. rather
D. like
9. (错误)
The dish wan’ t__________ me, so I felt still a little hungry after the supper.
A. in line for
B. in line with
C. on the line
D. line up
10. After hearing the news, I could not ____________ my work that whole afternoon.
A. concentrate in
B. set minds to
C. set my mind on
D. set my mind at
一、单项选择题（共10道小题，共100.0分）
1. Demand for electricity is at its _________ in July and August because a number of
air-conditioners are in use.
A. peak
B. hill
C. cliff
D. weight
2. (错误)
Extensive reporting on television has helped to _________ interest in a wide variety of sports and activities.
A. gather
B. generate
C. assemble
D. yield
3. In a sudden _________ of anger, the man tore up everything within reach.
A. attack
B. burst
C. split
D. blast
4. (错误)
The cost of the damage _________ our worst fears.
A. excelled
B. examined
C. exceeded
D. excess
5. (错误)
The police will give you a ticket if you __________ the speed limit.
A. break
B. exceed
C. upset
D. split
6. Lu Xun once said: “Cows _________on grass but what they produce is milk.”
A. afford
B. support
C. feed
D. supply
7. __________ that three people cannot move it.
A. So and huge the stone is
B. So is the huge stone
C. So huge the stone is
D. So huge is the stone
8. He looked for his missing wallet in the _________ houses for hours.
A. surroundings
B. surrounding
C. surround
D. surrounded
9. The tree in the picture is the_________ of life and the snake is the_________ of evil.
A. symbol, sign
B. sign，symbol
C. symbol，symbol
D. sign，sign
10. A driver should concentrate__________ the road while driving, or it’s easy to bring accidents.
A. to
B. on
C. for
D. in
北邮网络-操作系统原理-阶段作业三
一、单项选择题（共10道小题，共100.0分） 1. 不支持记录等结构的文件类型是 A. 顺序文件 B. 索引顺序文件 C. 索引文件 D. 哈希文件 2. 在I/O系统层次模型中处于最高的一个层次，负责所有设备I/O工作中均 要用到的共同的功能的模块是 A. 系统服务接口 B. I/O子系统 C. 设备驱动程序接口 D. 设备驱动程序 3. 在采用局部转换策略进行页面置换的系统中，一个进程得到3个页架。系 统采用先进先出的转换算法，该进程的页面调度序列为：1，3，2，6，2，5，6，4，6。如果页面初次装入时不计算为缺页，请问该进程在调度中会产生几次缺页。 A. 6次 B. 5次 C. 4次 D. 3次
4. 完成从物理页架号到虚地址的映射是 A. 页表 B. 反向页表 C. 多级页表 D. 快表 5. 下列设备中，（）为块设备。 A. 软盘驱动器 B. MODEM C. 声卡 D. 鼠标 6. 在下列的实存管理技术中，同一进程在连续地址存储的技术是 A. 可变分区多道管理技术 B. 多重分区管理 C. 简单分页 D. 简单分段
7. 采用简单分页系统的内存管理，页面的大小是8K字节。现有一个逻辑地 址A＝3580h，该进程的页表为 [0,5/1,6/2,1/3,0...]，则该逻辑地址对应的物理地址A'＝（） A. 0580h B. D580h C. 6580h D. 7580h 8. 对于实存管理技术，实际上它不具备的功能有： A. 主存分配 B. 地址转换和重定位 C. 存储保护和主存共享 D. 存储扩充 9. 在当前的计算机系统中，通常是按（）进行编址。 A. 位 B. 字节
北邮数理方程课件-第八章-Green函数法
第八章 Green函数法 8.2 基础训练 8.2.1 例题分析 例1求三维泊松方程的基本解． 解：Green函数满足的方程为 (8。1) 采用球坐标，并将坐标原点放在源点上． 由于区域是无界的，点源所产生的场应与方向无关，而只是r的函数，于是式(8.1)简化为当时，方程化为齐次的，即 易于求得其一般解为 (8。2) 取，不失一般性，得 (8。3) 考虑的情形．为此，对方程(8.1)在以原点为球心、为半径的小球体内作体积分 从而 而由散度定理 为的边界面） 有 故 将式(8.3)的结果代入上式，得 代入式(8.3)，于是
例2求二维泊松方程的基本解． 解：格林函数满足的方程为 (8。5) 采用极坐标，并将坐标原点放在源点上，则 与三维问题一样，G应只是r的函数，于是式(8。5)简化为 (8。6) 当时，解式(8。6)，得 当时，在以原点为中心、为半径的小圆内对方程(8。.5)两边作面积分，注意到二维情况下的散度定理为 为的边界） 类似于对三维情况的讨论，得 于是 (8.7) 例3求泊松方程在矩形区域内的狄氏问题的格林函数． 解：其格林函数的定解问题为 它是定解问题 当时的特例，而与定解问题(8-10) ~ (8.11)相应的本征值问题为 它的本征值和归一化的本征函数分别是 其中 在式(8.8)中，故根据式(8.7)，有
例4求解球的狄氏问题 (8.12) 解：此时方程的非齐次项，故由解的积分公式得定解问题(8.12)的解为 (8.13) 其中为球面，G为球的狄氏格林函数，它满足定解问题 (8.14) 故求u的问题就转化为求边界为球面的三维泊松方程的狄氏格林函数G的问题．而由上面所述的G的物理意义知，求G即要求在点置有正电荷的接地导体球内任意一点M处的电位，亦即要求感应电荷所产生的电位g，它满足 (8.15) 由物理学知识知，倘若在点关于球面的对称点（又称像点）放置一负点电荷，则由于在球外，它对球内电位的贡献必然满足拉氏方程．因此，只要适当选择q的大小，使之对边界面上电位的贡献与点的正电荷对边界面上电位的贡献等值，则对球内任一点电位的贡献即与g等效．为此，如图8-1所示，我们延长到，并记； ，使 即 则为关于球面的像点．显然，当M点在球面上时（如图8-2所示），,故有 (8.16) 从而有 即(8.17) 图8-1 图8-2 由式(8.17)可以看出，只要在点放置一负电荷，则它在球内直到球上任意一点
北邮网络学院大学英语2阶段作业3
一、阅读理解（共1道小题，共25.0分） 1. A pretty, well―dressed young lady stopped a taxi in a big square, and a said to the driver, "Do you see that young man at the other side of the square?" "Yes," said the taxi driver. The young man was standing outside a restaurant and looking impatiently (不耐烦地) at his watch every few seconds. "Take me over there," said the young lady. There were a lot of cars and buses in the square, so the taxi driver asked, "Are you afraid to cross the street?" "Oh, no!" said the young lady. "But I promised that I would meet the young man for lunch at one o' clock, and it is now a quarter to two. If I arrive in a taxi, it will at least seem as if I had tried not to be late." 1.How did the young woman get to the square? A.She arrived in a taxi. B.She drove there in a car. C.She got there by bus. D.The story doesn't tell us. 2.Why did the lady stop the taxi? A.Because she didn't want to be late for her appointment (约会). B.Because she wanted to get out of the taxi. C.Because she wanted to go to the restaurant in it. D.Because she was afraid of walking across the street. 3.The young man at the other side of the square_______. A.had probably been waiting for a long time B.had some problem with his watch C.was probably a waiter of the restaurant D.was someone the young lady didn't want to see 4.The young lady was_______. A.clever at making excuse B.not late at all C.45 minutes earlier D.15 minutes late 5.Had she tried not to be late? A.Yes, she had tried her best. B.No, she was just pretending that she had tried. C.Yes, she had tried but she was still late. D.No, she thought being late was better than being early.
北邮模式识别课堂作业答案(参考)
第一次课堂作业 1.人在识别事物时是否可以避免错识 2.如果错识不可避免，那么你是否怀疑你所看到的、听到的、嗅 到的到底是真是的，还是虚假的 3.如果不是，那么你依靠的是什么呢用学术语言该如何表示。 4.我们是以统计学为基础分析模式识别问题，采用的是错误概率 评价分类器性能。如果不采用统计学，你是否能想到还有什么合理地分类 器性能评价指标来替代错误率 1.知觉的特性为选择性、整体性、理解性、恒常性。错觉是错误的知觉，是在特定条件下产生的对客观事物歪曲的知觉。认知是一个过程，需要大脑的参与.人的认知并不神秘，也符合一定的规律，也会产生错误 2.不是 3.辨别事物的最基本方法是计算 . 从不同事物所具有的不同属性为出发点认识事物. 一种是对事物的属性进行度量，属于定量的表示方法(向量表示法 )。另一种则是对事务所包含的成分进行分析，称为定性的描述(结构性描述方法)。 4.风险 第二次课堂作业 作为学生，你需要判断今天的课是否点名。结合该问题(或者其它你熟悉的识别问题，如”天气预报”)，说明: 先验概率、后验概率和类条件概率 按照最小错误率如何决策 按照最小风险如何决策 ωi为老师点名的事件,x为判断老师点名的概率 1.先验概率: 指根据以往经验和分析得到的该老师点名的概率,即为先验概率 P(ωi ) 后验概率: 在收到某个消息之后，接收端所了解到的该消息发送的概率称为后验概率。 在上过课之后,了解到的老师点名的概率为后验概率P(ωi|x) 类条件概率:在老师点名这个事件发生的条件下,学生判断老师点名的概率p(x| ωi ) 2. 如果P(ω1|X)>P(ω2|X)，则X归为ω1类别 如果P(ω1|X)≤P(ω2|X)，则X归为ω2类别 3.1)计算出后验概率 已知P(ωi)和P(X|ωi)，i=1,…，c，获得观测到的特征向量X 根据贝叶斯公式计算 j=1,…，x
北邮第三次阶段作业大学英语2
1. People have been talking about health for a long time because people know the importance of it. People's understanding of health also becomes deeper with the progress in scientific research. Recently the term "health" has come to have a wider meaning than it used to. It no longer means just the absence of illness. Today, health means the well-being of your body, your mind and your relationship with other people. This new concept of health is closely related to another term----quality of life. Quality of life is the degree of overall satisfaction that a person gets from life. Why has the emphasis of health shifted from the absence of disease to a broader focus on the quality of a person's life？One reason for this has to do with the length and conditions of life that people can now expect. Medical advances have made it possible for people today to live longer, healthier lives. Imagine for a moment that you were born in the year 1900. You could have expected on average to live until about the age of 47. In contrast, if you were born in the year 1999, you could expect to live to the age of 75. 2. 1. ______leads to people's deeper understanding of health. 2. https://www.360docs.net/doc/e716724390.html,mon knowledge 2.Progress in scientific research 3.Better conditions of living 4.Quality of life 3. According to the passage, to people of today, health means______. 4. 1.absence of illness 2. a long life 3.good conditions of living 4.overall satisfaction with life
北邮网络学院工商管理英语练习题答案
北邮网络学院工商管理英语练习题答案 一、阅读理解（共1道小题，共25.0分） 1 (错误)People are so busy these days that many have no time to cook. This is a problem because many families love home cooking! A family meal brings everyone together. In some families, meals are often the only time everyone sees each other at the same time. Another reason people enjoy home cooking is that it is often a way of showing love. A parent who makes some cookies is not just satisfying a child's sweet tooth. She or he is sending a message. The message says, "I care about you enough to spend an hour making cookies that you will eat up in 15 minutes if I let you." There is also something about the smell of home cooking. The smell of home cooking pleases people of all ages. It makes most of us feel good and loved --- even if we are the ones doing the cooking! Next time you smell a cake being cooked, stop for a moment and pay attention to your mood（心情）. 1. Why do few people cook now? 1They have no time. 1They can buy food. 1Many people don?t like cooking. 1They d on?t like family meals. A parent spends an hour making cookies____. 1just to satisfy her or his child?s sweet tooth 1only to send a message 1to let a child eat up in 15 minutes 1often to show her or his love The writer thinks the smell of home cooking _____. 1makes us happy 1makes us be interested in cooking 1makes us pay attention to our mood 1makes us love others What?s the main idea of this passage? 1Family meals are important. 1How to make cookies. 1People are too busy to cook 1Homemade cookies taste better. Which of the following statements is NOT true according to the passage? 1There are quite a few reasons that people love home cooking. 1It becomes a problem that most families love home cooking. 1The smell of home cooking makes most of us feel good. 1 A family meal can bring the family members together. 试题分值：25.0 得分：[5, 5, 0, 5, 0] 提示：[1]A.细节题。本题问“为何现在没有多少人愿意下厨了?”中心词是“few people cook”。
北邮数学物理方法18-19期末试题B
北京邮电大学2018-2019学年第一学期 《数学物理方法》期末试题（B ） 注意：本试卷共5 道大题。答题时不必抄题，要注明题号，所有答案一律写在答题纸上，否则不计成绩。 一、 解答下列各题（每题6分，共36分） 1、 写出三类基本方程的最简单形式。 2、求解下列本征值问题的本征值和本征函数 ()()()()()() 02,2?λ??π??π?''Φ+Φ=???''Φ+=ΦΦ+=Φ??3、将Bessel 方程 222()0x y xy x m y λ'''++-= 化成Sturm-Liouville 型方程，并指出其核函数和权函数。 4、用达朗贝尔公式求下列定解问题的解 ()()()20,0,,0cos ,,0. tt xx x t u a u x t u x x u x e ?-=-∞<<∞>??==??5、设()f x 在区间[-1,1]上的有界且连续，并设 ()()()0Legendre n n n n f x f P x P x ∞ ==∑其中是多项式 试证明 ()()11 212n n n f P x f x dx -+= ?. 6、已知Bessel 函数的递推公式1[()]()m m m m d x J x x J x dx -=，试计算30()x J x dx ?。
二、研究细杆上的热传导问题。设杆上的初始温度是均匀的为0,u 然后保持杆的一端的温度为不变的0,u 而另一端则有强度为恒定的热流0q 进入，即求解定解问题 22200000,,,.x x x l t u u a t x q u u u k u u ===???=?????==???=?? （25分） 三、 求解下列定解问题 ()222220001,0,0,,,0.b t t u u u a b t u u u u f t ρρρρρρρ====??????=+<
北京邮电大学2009年操作系统期末试卷
北京邮电大学2008——2009学年第一学期 《操作系统》期末考试试题（A） 1.FILL IN BLANKS (10 points) 1.1 A _trap___ is a software-generated interrupt caused either by an error or by a specific request from a user program that an operating-system services be performed. 1.2 A ______ is used in Unix systems to notify a process that a particular event has occurred. 1.3 To manage the process executing, OS records the state and other information (e.g. the priority) of the process in . 1.4 The scheduling criteria include CPU utilization, throughput, turnaround time, waiting time, and response time .
1.5 For n concurrent processes that mutual exclusively use some resources, the code segmentations, in which the processes access the resources, are called deadlock . 1.6. The ___visual memory___ scheme enables users to run programs that are larger than actual physical memory, this allows the execution of a process that is not completely in memory. 1.7. The __FIFO___ page replacement algorithm associates with each page the time when that page was brought into memory. When a page must be replaced, the oldest page is chosen. 1.8The file system resides permanently on , which is designed to hold a large amount of data permanently. 1.9The file system itself is generally composed of many different levels, including the logical file system, the file-organization module, the and the I/O control. 1.10 T he kernel’s I/O subsystem provides numero us services. Among these are I/O scheduling, , caching, spooling, device reservation, and error handling, and name translation. 2.CHOICE ( 10 points ) 2.1 _____ operating systems have well defined, fixed time constraints. Processing must be done within the defined constrains, or the system will fail. A. Multimedia B. Real-time C. Clustered D. Network 2.2 Which one of the following OS is implemented based on microkernel structure? _____
北邮课表
2009级通信工程专业培养方案的执导教学计划 打开课组| 关闭课组 2009-2010学年 第一学期（秋季学期） [3200010]思想道德修养与法律基础 [3200020]中国近现代史纲要 [3310011]体育基础(上) [4110011]高等数学A(上) [4110071]线性代数 [4110081]高等代数 [1100310]大学计算机基础 [8200010]军事理论 [8300001]形势与政策1 [3112010]大学英语一级 [4110051]数学分析(上) 第二学期（春季学期） [3112020]大学英语二级 [3320011]体育基础(下) [4110021]高等数学A(下) [1201011]电路分析基础
[8200020]军训 [8300002]形势与政策2 [4120012]大学物理B(上) [3200030]毛泽东思想和中国特色社会主义理论体系概论 [3200031]毛泽东思想和中国特色社会主义理论体系概论(实践) [4110061]数学分析(下) [1100320]C++程序设计基础 第三学期（夏季学期） 2010-2011学年 第一学期（秋季学期） [3200040]马克思主义基本原理 [3330012]体育专项(上) [4120022]大学物理B(下) [4130021]物理实验(2) [1100330]数据结构 [1100520]计算机实习 [1201030]信号与系统 [1208011]电子测量与电子电路实验(上) [4110140]复变函数 [8300003]形势与政策3
[3112030]大学英语三级 [4130011]物理实验(1) [1100010]电子电路基础 第二学期（春季学期） [3112040]大学英语四级 [4110091]概率论与随机过程 [4110130]数理方程 [4110190]计算方法 [4110240]离散数学 [1100040]数字电路与逻辑设计 [1208021]数字电路与逻辑设计实验(上) [8300004]形势与政策4 [3112130]国家大学英语四级考试 [1100540]电路综合实验 [1208012]电子测量与电子电路实验(下) [1100550]电子工艺实习 [3340012]体育专项(下) [1100340]数据库技术与应用 [1100350]多媒体计算机应用基础 [1100020]数字信号处理 [1100030]通信电子电路
北邮大学英语2答案【精选】word版本
北邮大学英语2答案 【精选】
一、完形填空（共1道小题，共50.0分） 1.(错误) I first saw the baby panda when she was only 10 days old. She looked like a white mouse. We ____1___her Xi Wang. It means “hope”. When Xi Wang was born, she weighed____2___100 grams. Xi Wang drank her mothe r’s milk for as much as 14 hours a day. When she was six months old, she started to eat bamboo shoots (嫩芽) and ____3____. Eight months later, she was not a small baby any more. She grew into a____4___young panda and weighed 35 kilos. When Xi Wang was 20 months old, she had to look after herself _____5___ her mother had another baby. ____6_____, it is very difficult for pandas to live in the wild. Here are some of the _____7____that pandas like Xi Wang may have in the future. If hunters catch a panda, they will kill it for its fur. If farmers____8____trees and forests, pandas will have no place to live in. When mothers leave baby pandas alone, people will often take them away. People think that the baby pandas need ____9_____. If pandas are in danger, we should try our best to protect them. If we do____10_____, soon there will be no more pandas in the world!?? a. A.made B.called C.told D.kept 学生答案: B; 标准答 案: B b. A.quite
北邮大学英语2阶段作业2
A . anyone else B . anything C . some of the things D . anything else A . more larger, all B . much larger, that C . very larger, both D . larger, those
A . flooded B . were flooded C . was flooded D . flood √4. A . being B . C . having D . having A . happened to see B . was happened to see C . happened to be seen D . was happened to be seen
A . rather B . enough C . quite a D . fairly A . the much best B . much the most best C . the very best D . very the best A . will put off
B . will be put off C . will be put D . has put off A . When B . What time C . How often D . How long A . take good care of B . has taken good care of C . took good care of D . are taken good care of
北邮大学统考英语阶段作业3 2017.11.28
一、完形填空（共1道小题，共50.0分） Many students find the experience of attending university lectures to be a confusing and frustrating experience. The lecturer speaks for one or two hours, perhaps 1 the talk with slides, writing up important information on the blackboard, 2 reading material and giving out assignment. The new student sees the other students continuously writing on notebooks and 3 what to write. Very often the student leaves the lecture with notes which do not catch the main points and 4 become hard even for the students to understand. Most institutions provide courses which assist new students to develop the skills they need to be 5 listeners and note-takers. If these are unavailable, there are many useful study-skills guides which 6 learners to practice these skills independently. In all cases it is important to 7 the problem before actually starting your studies. It is important to acknowledge that most students have difficulty 8 acquiring the language skills required in college study. One way of 9 these difficulties is to attend the language and study-skills classes which most institutions provide throughout the academic year. Another basic strategy is to find a study partner 10 it is possible to identify difficulties, exchange ideas and provide support. 1. 1.illustrating 2.which 3.wonders 4.effective 5.distributing 学生答案:A; 标准答 案: A; 2.
北邮高级操作系统期末试卷
2017，2015,2013北邮高级操作系统 试题 学号： 姓名： 成绩： 、分布式操作系统中的透明性主要是什么？其中那些透明性容易实现？哪些难实现？???分? 难点： 、创建一个分布式数据库系统可提供有效的存取手段来操纵这些结点上的子数据库。 、不确定性，控制比较复杂，尤其是在资源管理上要附加许多协调操作—资源属于局部工作站，性能、可靠性对网络的依赖性强，安全保密——基础不好。用户掌握有许软件接口，相应的应用软件较少，需要大力开发。 、分布式互斥中集中式算法、分布式算法、令牌算法。分析一下其中那个算法比较实用，为什么？???分? 集中式算法：集中式算法借鉴了集中式互斥算法的思想，在分布式系统
中，选出一个进程为协调者 ?通过科学的分析制定一套规则? 。协调者对所有的请求进行排队并根据一定的规则授予许可。协调者接受请求以后，检查临界区内的资源是否被其他进程占用。如果是，则它将当前请求进程插入到对应临界资源的请求队列中 否则，回复一个同意消息给请求进程，通知它可以访问该临界资源。该算法通俗易懂，既能够杜绝死锁、饥饿等现象发生，又能保证资源的互斥访问顺利进行。 但是它也有缺点，由于是集中式管理，所以一旦管理进程出现故障，则整个系统将处于瘫痪状态。因此，管理进程的性能完全决定了算法的效率，应用范围小，难以普及。 分布式算法：分布式算法中运用到广播请求通信，当进程想请求共享资源时，需要首先建立三个变量 准备进入临界区，实时时间和处理器号，并利用广播通信发送给正在运行的所有进程。该算法的核心思想如下 当进程想进入临界区时 要建立一个包括进入的临界区名字、处理器号和当前时间的消息 并把消息发送给所有其它进程。当进程接收到另一个进程的请求消息时 将分下面三种情况来区别对待 ?若接收者不在临界区中 也不想进入临界区 就向发送者发送 ?消息； ?若接收者已经在临界区内就不必回答 而是负责对请求消息排队； ?若接收者要进入临界区 但还没进入 它就会把接收的消息和它发送的消息的时间戳进行对比 取小的那个。如果接收的消息时间戳小 就发 ?消息 如果发送的消息时间戳小 那么接收者负责排列请求队列而不发送任何消息。当进程接收到允许消息时 它就进入临界区。从临界区退出时 向队列中的所有进程发送 ?消息 并将自己从队列中删除。该算法可以保证访问临界区的互斥性以及无死锁进程、无饥饿进程。但是这种算法有个严重的缺点是算法太复杂并且不健壮 任何一个进程崩溃都会影响到算法的正确性。二是令牌丢失 令牌算法：令牌算法中引入了令牌，所有的进程组成一个环模型，环中每个进程需要知道它的下一个位置的节点的名称。令牌在环上顺序传递，当
北邮数理方程课件第三章的分离变量法
第三章 分离变量法 3。2 基础训练 3.2.1 例题分析 例1 解下列定解问题： ???? ?????=??-==??=><
其中A ，B 为积分常数，（7）代入（6）中边界条件，得 00 A B Ae +=???-+=?? （8） 由（8）得A=B=0，得X （x ）=0，为平凡解，故不可能有0λ<。 (2) 当0λ=时，（6）式中方程的通解是 ()X x Ax B =+ 由边界条件得A=B=0，得X （x ）=0，为平凡解，故也不可能有0λ=。 （3）当 02 >=βλ时，上述固有值问题有非零解．此时式（6）的通解为 x B x A x X ββsin cos )(+= 代入条件（6）中边界条件，得 0cos ,0==l B A β 由于 0≠B ，故 0cos =l β，即 ),2,1,0(212Λ=+= n l n πβ 从而得到一系列固有值与固有函数 2 2 24)12(l n n πλ+= ),2,1,0(2)12(sin )(Λ=+=n x l n B x X n n π 与这些固有值相对应的方程（3）的通解为 ),2,1,0(2)12(sin 2)12(cos )(Λ=+'++'=n t l a n D t l a n C t T n n n ππ 于是，所求定解问题的解可表示为 x l n t l a n D t l a n C t x u n n n 2)12(sin 2)12(sin 2)12(cos ),(0πππ+??? ? ? +++=∑∞ = 利用初始条件确定其中的任意常数n n D C ,，得 0=n D
北邮网络英语第6阶段作业
√1. Mrs Smith warned her daughter ______ after drinking. 正确答案：A 题目注释 A . never to drive B . to never drive C . never driving D . never drive √2. She was glad to see her child well______________ . 正确答案：B 题目注释 A . take care of B . taken care of C . taken care D . taking care or √3. Don't let him ________ you_____for a long time. 正确答案：C 题目注释 A . to make, wait B . make, to wait C . make, wait D . to make, to wait √4. The sentence needs_____________ . 正确答案：C 题目注释 A . to improve B . improve C . improving D . improved √5. Napoleon spoke so loudly as to ________ in front of his soldiers. 正确答案：B 题目注释 A . hear B . be heard
C . listen D . be listened √6. Now the need_______ other people's language is becoming greater and greater. 正确答案：A 题目注释 A . to learn B . learning C . to be learned D . being learned √7. The police forbid ______ here. 正确答案：B 题目注释 A . park B . parking C . to park D . to be parked √8. My brother regretted _______ a lecture given by Professor Liu. 正确答案：A 题目注释 A . missing B . to miss C . missed D . being missed √9. We found many people________ in the meeting room. 正确答案：D 题目注释 A . seat B . seating C . to seat D . seated √10. My hometown is found __________. 正确答案：D 题目注释