习题课2答案
计算机组成原理习题课2
10. 32位字长的浮点数，其中阶码8位(含1位阶符)，尾数24位(含 1位数符)，则其对应的最大正数为 ① ，最小负数为 ② ，最小 的绝对值为 ③ ；若机器数采用补码表示，且尾数为规格化形式， 则对应的最大正数为 ④ ，最小正数为 ⑤ ，最小负数为 ⑥ 。
A．2127(1-2-23) D．-2+127 B．-2127(1-2-23) E. 2-128×2-23 C． 2-129 F. 2-127×2-23
41．小数(0. 65625)十 等于_______。 A．(0. 11101)二 B．(0. 10101)二 C．(0. 00101)二 D．(0. 10111)二 答案：B 42. (84)十 等于______。 A．(10100100)二 B．(224)八 C．(054)十六 D．(1210)四 答案：C 44 二进制数11001011 等于十进制的_____。 A．395 B．203 C．204 D．394 答案：B 47． (20．8125)十 = ( ________ ) 二 。 A. 1010.1101 B. 10100.1011 C. 10100.1101 D.1010.1011 答案：C 48．补码10110110代表的是十进制负数____。 A． -74 B． -54 C． -68 D． -48 答案：A
9. 用n+1位字长表示定点数(其中1位为符号位)，它所能表示的 整数范围是 ① ，它所能表示的小数范围是 ② 。
A．0≤ |N| ≤ 2n-l
C. 0≤ |N| ≤ 1- 2-(n+l) ②D 答案： ① A
B． 0≤ |N| ≤ 2n+1 -l
D. 0≤ |N| ≤ 1-2-n （此处为真值表示）
C． -263 ~ 263(1-2-9)
国际财务管理（英文版）课后习题答案2
IM-1 CHAPTER 1 GLOBALIZATION AND THE MULTINATIONAL FIRMSUGGESTED ANSWERS TO END-OF-CHAPTER QUESTIONSQUESTIONS 1. Why is it important to study international financial management? Answer: We We are are are now now now living living living in in in a a a world world world where where where all all all the the the major major major economic economic economic functions, functions, functions, i.e., i.e., i.e., consumption, consumption, production, production, and and and investment, investment, investment, are are are highly highly highly globalized. globalized. It It is is is thus thus thus essential essential essential for for for financial financial financial managers managers managers to to to fully fully understand understand vital vital vital international international international dimensions dimensions dimensions of of of financial financial financial management. management. This This global global global shift shift shift is is is in in in marked marked contrast to a situation that existed when the authors of this book were learning finance some twenty years ago. At that time, most professors customarily (and safely, to some extent) ignored international aspects of finance. This mode of operation has become untenable since then. 2. How is international financial management different from domestic financial management? Answer: There are three major dimensions that set apart international finance from domestic finance. They are: 1. foreign exchange and political risks, 2. market imperfections, and 3. expanded opportunity set. 3. Discuss the three major trends that have prevailed in international business during the last two decades. Answer: The 1980s brought a rapid integration of international capital and financial markets. Impetus for globalized financial markets initially came from the governments of major countries that had begun to deregulate their foreign exchange and capital markets. The economic integration and globalization that began in the eighties is picking up speed in the 1990s via privatization. Privatization is the process by which a country divests itself of the ownership and operation of a business venture by turning it over to the free market system. Lastly, trade liberalization and economic integration continued to proceed at both the regional and global levels. IM-2 4. How How is is is a a a country‟s country‟s economic economic well well well-being -being -being enhanced enhanced enhanced through through through free free free international international international trade trade trade in in in goods goods goods and and services? Answer: According According to to to David David David Ricardo, Ricardo, Ricardo, with with with free free free international international international trade, trade, trade, it it it is is is mutually mutually mutually beneficial beneficial beneficial for for for two two countries to each specialize in the production of the goods that it can produce relatively most efficiently and and then then then trade trade trade those those those goods. goods. By By doing doing doing so, so, so, the the the two two two countries countries countries can can can increase increase increase their their their combined combined combined production, production, which which allows allows allows both countries both countries to to consume consume consume more more more of of of both both both goods. goods. This This argument argument argument remains remains remains valid even valid even if if a a country country can can can produce produce produce both both both goods goods goods more more more efficiently efficiently efficiently than than than the the the other other other country. country. International International trade trade trade is is is not not not a a …zero …zero--sum‟ game in which one country benefits at the expense of another country. Rather, international trade could be an …increasing -sum‟ game at which all players become winners.5. What considerations might limit the extent to which the theory of comparative advantage is realistic? Answer: The The theory theory theory of of of comparative comparative comparative advantage advantage advantage was was was originally originally originally advanced advanced advanced by by by the the the nineteenth nineteenth nineteenth century century economist David Ricardo as an explanation for why nations trade with one another. The theory claims that economic well-being is enhanced if each country‟s citizens produce what they have a comparative advantage in producing relative to the citizens of other countries, and then trade products. Underlying the the theory theory theory are are are the the the assumptions assumptions assumptions of of of free free free trade trade trade between between between nations nations nations and and and that that that the the the factors factors factors of of of production production production (land, (land, buildings, labor, technology, and capital) are relatively immobile. To the extent that these assumptions do not hold, the theory of comparative advantage will not realistically describe international trade. 6. What are multinational corporations (MNCs) and what economic roles do they play? Answer: A A multinational multinational multinational corporation corporation corporation (MNC) (MNC) (MNC) can can can be be be defined defined defined as as as a a a business business business firm firm firm incorporated incorporated incorporated in in in one one country country that that that has has has production production production and and and sales sales sales operations operations operations in in in several several several other other other countries. countries. countries. Indeed, Indeed, Indeed, some some some MNCs MNCs MNCs have have operations in dozens of different countries. MNCs obtain financing from major money centers around the the world world world in in in many many many different different currencies currencies to to to finance finance finance their their their operations. operations. Global Global operations operations operations force force force the the treasurer‟s office office to to to establish establish establish international international international banking banking banking relationships, relationships, relationships, to to to place place place short short short-term -term -term funds funds funds in in in several several currency denominations, and to effectively manage foreign exchange risk. IM-3 7. Mr. Ross Perot, a former Presidential candidate of the Reform Party, which is a third political party in the the United United United States, States, States, had had had strongly strongly strongly objected objected objected to to to the the the creation creation creation of of of the the the North North North American American American Trade Trade Trade Agreement Agreement (NAFTA), which nonetheless was inaugurated in 1994, for the fear of losing American jobs to Mexico where it is much cheaper to hire workers. What are the merits and demerits of Mr. Perot‟s position on NAFTA? Considering the recent economic developments in North America, how would you assess Mr. Perot‟s position on NAFTA?Answer: Answer: Since Since Since the the the inception inception inception of of of NAFTA, NAFTA, NAFTA, many many many American American American companies companies companies indeed indeed indeed have have have invested invested invested heavily heavily heavily in in Mexico, Mexico, sometimes relocating production from the United sometimes relocating production from the United States States to Mexico. Although this to Mexico. Although this might have temporarily temporarily caused caused caused unemployment unemployment unemployment of of of some some some American American American workers, workers, workers, they they they were were were eventually eventually eventually rehired rehired rehired by by by other other industries often for higher wages. Currently, the unemployment rate in the U.S. is quite low by historical standard. At the same time, Mexico has been experiencing a major economic boom. It seems clear that both both Mexico Mexico Mexico and and and the the the U.S. U.S. U.S. have have have benefited benefited benefited from from from NAFTA. NAFTA. NAFTA. Mr. Mr. Mr. Perot‟s Perot‟s concern concern appears appears appears to to to have have have been been been ill ill founded. 8. In 1995, a working group of French chief executive officers was set up by the Confederation of French Industry (CNPF) and the French Association of Private Companies (AFEP) to study the French corporate governance governance structure. structure. structure. The The The group group group reported reported reported the the the following, following, following, among among among other other other things things things “The “The “The board board board of of of directors directors should not simply aim at maximizing share values as in the U.K. and the U.S. Rather, its goal should be to serve serve the the the company, company, company, whose whose whose interests interests interests should should should be be be clearly clearly clearly distinguished distinguished distinguished from from from those those those of of of its its its shareholders, shareholders, employees, creditors, suppliers and clients but still equated with their general common interest, which is to safeguard the prosperity and continuity of the company”. Evaluate the above recommendation of the working group. Answer: Answer: The The The recommendations recommendations recommendations of of of the the the French French French working working working group group group clearly clearly clearly show show show that that that shareholder shareholder shareholder wealth wealth maximization is not a universally accepted goal of corporate management, especially outside the United States and possibly a few other Anglo-Saxon countries including the United Kingdom and Canada. To some extent, this may reflect the fact that share ownership is not wide spread in most other countries. In France, about 15% of households own shares. IM-4 9. Emphasizing the importance of voluntary compliance, as opposed to enforcement, in the aftermath of corporate scandals, e.g., Enron and WorldCom, U.S. President George W. Bush stated that while tougher laws might help, “ultimately, the ethics of American business depends on the conscience of America‟s business leaders.” Describe your view on this statement. Answer: There can be different answers to this question. If business leaders always behave with a high ethical standard, many of the corporate scandals we have seen lately might not have happened. Since we cannot cannot fully fully fully depend depend depend on on on the the the ethical ethical ethical behavior behavior behavior on on on the part the part of of business business business leaders, leaders, leaders, the the the society society society should should should protect protect itself itself by by by adopting adopting adopting the the the rules/regulations rules/regulations rules/regulations and and and governance governance governance structure that structure that would would induce induce induce business business business leaders leaders leaders to to behave in the interest of the society at large. 10. Suppose you are interested in investing in shares of Nokia Corporation of Finland, which is a world leader leader in in in wireless wireless wireless communication. communication. communication. But But But before before before you you you make make make investment investment investment decision, decision, decision, you you you would would would like like like to to to learn learn about the company. Visit the website of CNN Financial network () and collect information information about about about Nokia, Nokia, Nokia, including including including the the the recent recent recent stock price stock price history history and and and analysts‟ analysts‟ views views of the of the compa company. ny. Discuss what you learn about the company. Also discuss how the instantaneous access to information via internet would affect the nature and workings of financial markets. Answer: As students might have learned from visiting the website, information is readily available even for for foreign foreign foreign companies companies companies like like like Nokia. Nokia. Nokia. Ready Ready Ready access access access to to to international international international information information information helps helps helps integrate integrate integrate financial financial markets, dismantling barriers to international investment and financing. Integration, however, may help a financial shock in one market to be transmitted to other markets. IM-5 MINI CASE: NIKE‟S DE CISION Nike, a U.S.-based company with a globally recognized brand name, manufactures athletic shoes in such such Asian Asian Asian developing developing developing countries countries countries as as as China, China, China, Indonesia, Indonesia, Indonesia, and and and Vietnam Vietnam Vietnam using using using subcontractors, subcontractors, subcontractors, and and and sells sells sells the the products in the U.S. and foreign markets. The company has no production facilities in the United States. In In each each each of of of those those those Asian Asian Asian countries countries countries where where where Nike Nike Nike has has has production production production facilities, facilities, facilities, the the the rates rates rates of of of unemployment unemployment unemployment and and underemployment underemployment are are are quite quite quite high. high. high. The The The wage wage wage rate rate rate is is is very very very low low low in in in those those those countries countries countries by by by the the the U.S. U.S. U.S. standard; standard; hourly wage rate in the manufacturing sector is less than one dollar in each of those countries, which is compared with about $18 in the U.S. In addition, workers in those countries often are operating in poor and unhealthy environments and their rights are not well protected. Understandably, Asian host countries are are eager eager eager to to to attract attract attract foreign foreign foreign investments investments investments like like like Nike‟s Nike‟s Nike‟s to to to develop develop develop their their their economies economies economies and and and raise raise raise the the the living living standards of their citizens. Recently, however, Nike came under a world-wide criticism for its practice of hiring workers for such a low pay, “next to nothing” in the words of critics, and condoning poor working conditions in host countries. Evaluate Evaluate and and and discuss discuss discuss various various various …ethical‟ …ethical‟ as as well well well as as as economic economic economic ramifications ramifications ramifications of of of Nike‟s Nike‟s decision decision to to invest in those Asian countries. Suggested Solution to Nike‟s DecisionObviously, Obviously, Nike‟s Nike‟s investments investments in in in such such such Asian Asian Asian countries countries countries as as as China, China, China, Indonesia, Indonesia, Indonesia, and and and Vietnam Vietnam Vietnam were were motivated to take advantage of low labor costs in those countries. While Nike was criticized for the poor working working conditions conditions conditions for for for its its its workers, workers, workers, the the the company company company has has has recognized recognized recognized the the the problem problem problem and and and has has has substantially substantially improved the working environments recently. Although Nike‟s workers get paid very low wages by t he Western standard, they probably are making substantially more than their local compatriots who are either under- or unemployed. While Nike‟s detractors may have valid points, one should not ignore the fact that the company is making contributions to the economic welfare of those Asian countries by creating job opportunities. IM-6 CHAPTER 1A THEORY OF COMPARATIVE ADVANTAGESUGGESTED SOLUTIONS TO APPENDIX PROBLEMSPROBLEMS 1. Country C can produce seven pounds of food or four yards of textiles per unit of input. Compute the the opportunity cost of producing food instead of textiles. opportunity cost of producing food instead of textiles. Similarly, compute the opportunity cost of producing textiles instead of food. Solution: The opportunity cost of producing food instead of textiles is one yard of textiles per 7/4 = 1.75 pounds of food. A pound of food has an opportunity cost of 4/7 = .57 yards of textiles. 2. Consider the no-trade input/output situation presented in the following table for Countries X and Y. Assuming that free trade is allowed, develop a scenario that will benefit the citizens of both countries. IM-7 INPUT/OUTPUT WITHOUT TRADE _______________________________________________________________________ Country X Y Total ________________________________________________________________________ I. Units of Input (000,000) _______________________ ______________________________ Food 70 60 Textiles 40 30 ________________________________________________________________________ II. Output per Unit of Input (lbs or yards) ______________________ ______________________ ______________________________ ______________________________ Food 17 5 Textiles 5 2 ________________________________________________________________________ III. Total Output (lbs or yards) (000,000) ______________________ ______________________ ______________________________ ______________________________ Food 1,190 300 1,490 Textiles 200 60 260 ________________________________________________________________________ IV . Consumption (lbs or yards) (000,000) _____________________ ______________________________ Food 1,190 300 1,490 Textiles 200 60 260 ________________________________________________________________________ IM-8 Solution: Examination of the no-trade input/output input/output table table indicates that Country X X has has has an an absolute advantage advantage in in in the the the production production production of of of f f ood ood and and and textiles. textiles. Country Country X X X can can can “trade “trade “trade off” off” off” one one one unit unit unit of of of production production needed needed to to to produce produce produce 17 17 17 pounds pounds pounds of of of food food food for for for five five five yards yards yards of of of textiles. textiles. Thus, Thus, a a a yard yard yard of of of textiles textiles textiles has has has an an opportunity cost of 17/5 = 3.40 pounds of food, or a pound of food has an opportunity cost of 5/17 = .29 yards of textiles. Analogously, Country Y has an opportunity cost of 5/2 = 2.50 pounds of food per yard of textiles, or 2/5 = .40 yards of textiles per pound of food. In terms of opportunity cost, it is clear that Country X is relatively relatively more more more efficient in producing food and efficient in producing food and Country Y is relatively more efficient in producing producing textiles. textiles. textiles. Thus, Thus, Thus, Country Country Country X X X (Y) (Y) (Y) has has has a a a comparative comparative comparative advantage advantage advantage in in in producing producing producing food food food (textile) (textile) (textile) is is comparison to Country Y (X). When there are no restrictions or impediments to free trade the economic-well being of the citizens of both countries is enhanced through trade. Suppose that Country X shifts 20,000,000 units from the production of textiles to the production of food where it has a comparative advantage and that Country Y shifts shifts 60,000,000 60,000,000 60,000,000 units units units from from from the the the production production production of of of food food food to to to the the the production production production of of of textiles textiles textiles where where where it it it has has has a a comparative comparative advantage. advantage. Total output will now be (90,000,000 x 17 =) 1,530,000,000 pounds of food and [(20,000,000 x 5 =100,000,000) + (90,000,000 x 2 =180,000,000) =] 280,000,000 yards of textiles. Further suppose that Country X and Country Y agree on a price of 3.00 pounds of food for one yard of textiles, and that Country X sells Country Y 330,000,000 pounds of food for 110,000,000 yards of textiles. Under Under free free free trade, trade, trade, the the the following following following table table table shows shows shows that that that the the the citizens citizens citizens of of of Country Country Country X X X (Y) (Y) (Y) have have have increased increased increased their their consumption of food by 10,000,000 (30,000,000) pounds and textiles by 10,000,000 (10,000,000) yards. IM-9 INPUT/OUTPUT WITH FREE TRADE __________________________________________________________________________ Country X Y Total __________________________________________________________________________ I. Units of Input (000,000) _______________________ ________________________________ Food 90 0 Textiles 20 90 __________________________________________________________________________ II. Output per Unit of Input (lbs or yards) ______________________ ______________________ ________________________________ ________________________________ Food 17 5 Textiles 5 2 __________________________________________________________________________ III. Total Output (lbs or yards) (000,000) _____________________ ________________________________ Food 1,530 0 1,530 Textiles 100 180 280 __________________________________________________________________________ IV . Consumption (lbs or yards) (000,000) _____________________ ________________________________ Food 1,200 330 1,530 Textiles 210 70 280 __________________________________________________________________________ 。
《应用数学基础》 (谢政 著) 课后习题答案 国防工业出版社习题2解答
⎡λ + α ⎢ 0 ⎢ ⎢ 0 ⎢ ⎣ 0
0 λ +α 0 0
1 0 λ +α 0
0 ⎤ 1 ⎥ ⎥． 0 ⎥ ⎥ λ +α ⎦
+ 3i ( −1)] 0 −8 ⎤ [[ 2 −(λ + 1) λ + 11⎤ ⎡ 1 ⎡λ − 3 2 i ( −1)] 1,2 ⎢ ⎥ [ ] 0 →⎢ −8 ⎥ 解：(1) ⎢λ − 3 ⎥ ⎢ −3 λ + 1 −6 ⎥ ⎯⎯⎯⎯ ⎢ ⎥ ⎢ ⎥ λ λ − + − + 2 0 5 2 0 5 ⎣ ⎦ ⎣ ⎦
(2) 设目前农村人口与城镇人口相等，即 ⎢
解 (1) ⎢
q ⎤ ⎡ xn ⎤ ⎡ xn +1 ⎤ ⎡1 − p =⎢ ⎥ ⎥⎢ ⎥. ⎣ yn +1 ⎦ ⎣ p 1 − q ⎦ ⎣ yn ⎦ −q q ⎤ λ −1+ p ⎡1 − p = = (λ − 1)(λ − 1 + p + q) , ⎥ −p λ −1+ q ⎣ p 1− q⎦
Aα = λα , A α = A
m
m −1
( Aα ) = Am −1λα = λ Am −1α = λ mα
7. 将下列矩阵酉对角化．
A−1α = λ −1α
− 2 ，对应的特征向量分别为 (0,1, −i ) T , ( 2i,1, i ) T , (− 2i,1, i ) T ，由于此三个向量分
(2)
λI − ⎢
λ1 = 1, λ2 = 1 − p − q, ξ1 = ( q, p ) T , ξ 2 = (1, −1)T ,因此
q ⎤ ⎡ q 1 ⎤ ⎡1 0 ⎤ ⎡ q 1 ⎤ ⎡1 − p ⎢ p −1⎥ ⎢ p 1 − q ⎥ ⎢ p −1⎥ = ⎢ 0 1 − p − q ⎥ , ⎦ ⎣ ⎦ ⎣ ⎦⎣ ⎦ ⎣
金融衍生工具_课程习题答案(2)
资料范本本资料为word版本，可以直接编辑和打印，感谢您的下载金融衍生工具_课程习题答案(2)地点：__________________时间：__________________说明：本资料适用于约定双方经过谈判，协商而共同承认，共同遵守的责任与义务，仅供参考，文档可直接下载或修改，不需要的部分可直接删除，使用时请详细阅读内容第一章1、衍生工具包含几个重要类型？他们之间有何共性和差异？2、请详细解释对冲、投机和套利交易之间的区别，并举例说明。
3、衍生工具市场的主要经济功能是什么？4、“期货和期权是零和游戏。
”你如何理解这句话？习题答案1、期货合约：：也是指交易双方按约定价格在未来某一期间完成特定资产交易行为的一种方式。
期货合同是标准化的在交易所交易，远期一般是OTC市场非标准化合同，且合同中也不注明保证金。
主要区别是场内和场外；保证金交易。
二者的定价原理和公式也有所不同。
交易所充当中间人角色，即买入和卖出的人都是和交易所做交易。
特点：T＋0交易；标准化合约；保证金制度（杠杆效应）；每日无负债结算制度；可卖空；强行平仓制度。
1）确定了标准化的数量和数量单位、2）制定标准化的商品质量等级、（3）规定标准化的交割地点、4）规定标准化的交割月份互换合约：是指交易双方约定在合约有效期内，以事先确定的名义本金额为依据，按约定的支付率（利率、股票指数收益率）相互交换支付的约定。
例如，债务人根据国际资本市场利率走势，将其自身的浮动利率债务转换成固定利率债务，或将固定利率债务转换成浮动利率债务的操作。
这又称为利率互换。
互换在场外交易、几乎没有政府监管、互换合约不容易达成、互换合约流动性差、互换合约存在较大的信用风险期权合约：指期权的买方有权在约定的时间或时期内，按照约定的价格买进或卖出一定数量的相关资产，也可以根据需要放弃行使这一权利。
为了取得这一权利，期权合约的买方必须向卖方支付一定数额的费用，即期权费。
期权主要有如下几个构成因素①执行价格（又称履约价格，敲定价格〕。
图论习题答案2
第四次作业
四(13).设M是二分图G的最大匹配，则 | M || X | max| S | | N ( S )| ，
SX
证明： | X | max| S | | N ( S )| min(| X | | S |) | N ( S )| ，而（X - S ) N ( S )是G的一个覆盖，则 min(| X | | S |) | N ( S )|是G的最小覆盖，
第七次作业
• 五(28).设sn是满足下列条件的最小整数，把 {1,2,...,sn}任划分成n个子集后，总有一个子集 中含有x+y=z的根，求s1,s2,s3是多少？ • 解：n=1,枚举得s1=2; • s2=5 • s3=14
第七次作业
五(34).求证r(k, l) = r(l, k) 证明：若G含有K k 子图，则G c 含有k个顶点的独立集；若G含有 l个顶点的独立集，则G c 含有K l 子图。则命题成立。
五 (13).若 是单图 G 顶的最小次数，证明； 若 1则存在 1边着色， 使与每顶关联的边种有 1种颜色。 反证法：假设在 v1处无 i 0色 设 C (E 1 , E 2 ,..., E 1 )为 G 的( 1) 最佳边着色 第一步：构造点列： v1 , v 2 ,..., v h , v h 1 ,....., vl ,.... v1处无 i 0色， v j v j 1着 i j色，且在 v j点处 i j 色重复出现，可知在 v j1处仅一 个 i j色；证明如下： 用反证法证明，假设在 v j1处 i j色重复出现，将 v j v j 1改成 v j 所关联的边 没有的颜色 im，则可以对图 G 的找色进行改善。与 C 是最佳边着色矛盾， 假设不成立。 又 是单图 G 顶的最小次数，则必存 在最小整数 h使得 i h i l 第二步：着色调整： v j v j 1着 i j-1色 ( j 1,2,..., h )，所得新着色为 C ' 在 C '中， v1处多了个 i 0色， v h 1处少了个 i h 色，其他点的边着色数 不变， 所以 C ' 还是 1最佳边着色
南京邮电大学数据库系统课后习题答案2
4.30 设有关系模式R(ABCD)，其上的FD集为 ② F={AB→C，C→A，C→D}， ρ＝{ACD, BC} ⑤ F={A→B，B→C，C→D}， ρ＝{AB,AD,CD}
解② ：(1)R的关键码 AB、BC (2) ρ中有R1(ACD)， R2(BC)
R1∩R2=C， R1－R2=AD， 由F经合并性推理得： C→AD，ρ无损
F2={职工编号→部门名，部门名→部门经理} Key2: 职工编号, R2无部分依赖，达2NF
(3)分解成3NF R1无传递依赖，达3NF R2中：职工编号→部门经理 是传递依赖关系
将R2分解为3NF模式集 R21(职工编号,部门名) R22(部门名，部门经理 )
ρ＝{(职工编号,日期,日营业额)， (职工编号,部门名)，(部门名,部门经理)}
R2(CNO, TNAME, TADDR) } F2={CNO→TNAME,TNAME→TADDR}, KEY=(CNO) ρ中R1、R2的所有属性都是原子的，且没有非 主属性对候选键的部分函数依赖，达到2NF;
(3) 试把R分解成3NF模式集，并说明理由;
ρ={ R1(SNO, CNO, GRADE) , F1={{SNO,CNO}→GRADE}, KEY=(SNO, CNO) R21(CNO, TNAME) , F21={CNO→TNAME}, KEY=(CNO)
F={ { SNO,CNO }→GRADE ， CNO→TNAME ， TNAME→TADDR }
KEY={ SNO,CNO }
(2) 试把R分解成2NF模式集，并说明理由;
ρ={ R1(SNO, CNO, GRADE) , F1={{ SNO,CNO }→GRADE}, KEY=(SNO, CNO)
《现代控制理论》课后习题答案2
( sI − A) −1 =
1 adj( sI − A) det( sI − A)
(1)
式（1）中的 adj( sI − A) 和 det( sI − A) 可分别写成以下形式：
adj( sI − A) = H n −1s n −1 + H n − 2 s n − 2 + " + H 0 det( sI − A) = s + an −1s
故
Φ (t ) = α 0 (t ) I + α1 (t ) A + α 2 (t ) A2
⎡ −2tet + e 2t ⎢ = ⎢ −2(1 + t )et + 2e 2t ⎢ −2(2 + t )et + 4e 2t ⎣
(3t + 2)et − 2e 2t (3t + 5)et − 4e 2t (3t + 8)et − 8e 2t
n n −1
(2) (3) (4)
+ " + a0
，可得 将式（1）两边分别左乘 det( sI − A)( sI − A) ，并利用式（2）和（3）
Is n + an −1 Is n −1 + " + a0 I = H n −1s n + ( H n − 2 − AH n−1 ) s n − 2 + " + ( H 0 − AH1 )s − AH 0
e jt = a0 (t ) + a1 (t ) j ， e − jt = a0 (t ) − a1 (t ) j
而
e jt = cos t + j sin t ， e− jt = cos t − j sin t 因此， a0 (t ) = cos t ， a1 (t ) = sin t 。由此得到状态转移矩阵 ⎡ cos t sin t ⎤ Φ (t ) = e At = a0 (0) I + a1 (t ) A = ⎢ ⎥ ⎣ − sin t cos t ⎦
计算理论复习课2习题---答案
第三章 上下文无关语言与下推自动机a. {w | w 至少含有3个1} S →A1A1A1A A →0A|1A|εb. {w | w 以相同的符号开始和结束}S →0A0|1A1 A →0A|1A|εc. {w | w 的长度为奇数}0, ε→ε0,ε→ε 0,ε→ε1,ε→ε0,ε→εS →0A|1A A →0B|1B|ε B →0A|1Ad.{w | w 的长度为奇数且正中间的符号为0} S →0S0|1S1|0S1|1S0|0e.{w | wS →A1AA →0A1|1A0|1A|AA|εf.{w | w=w R }S →0S0|1S1|1|0g.空集 S →S3.6 给出产生下述语言的上下文无关文法： a ． 字母表{a,b}上a 的个数是b 的个数的两倍的所有字符串组成的集合。
S →bSaSaS|aSbSaS|aSaSbS|εb ．语言{a n b n |n ≥0}的补集。
见问题3.25中的CFG: S →aSb|bY|Ta T →aT|bT|εc ．{w#x | w, x ∈{0,1}*且w R 是x 的子串}。
S →UV0,ε→0,0→0,ε→1,0→0,1→0,ε→0,0→U→0U0|1U1|WW→W1|W0|#V→0V|1V|εd．{x1#x2#⋯#x k|k≥1, 每一个x i∈{a,b}* , 且存在i和j使得x i＝x j R}。
S→UVWU→A|εA→aA|bA|#A|#V→aVa|bVb|#B|#B→aB|bB|#B|#W→B|ε3.14解：添加新起始变元S0, 去掉B→εS0→A S0→AA→BAB|B|εA→BAB|AB|BA|B|εB→00|εB→00去掉A→ε, 去掉A→BS0→A S0→AA→BAB|AB|BA|B|BB A→BAB|AB|BA|00|BBB→00 B→00去掉S0→A, 添加新变元S0→BAB|AB|BA|00|BB S0→VB|AB|BA|UU|BBA→BAB|AB|BA|00|BB A→VB|AB|BA|UU|BBB→00 B→UUV→BAU→03.15 证明上下文无关语言类在并,连接和星号三种正则运算下封闭---答案。
课后习题答案 (2)
第1章一、单项选择题1．对项目而言，“一次性”是指（ A ）。
A．每个项目都有明确的起止时间 B．项目周期短 C．项目将在未来不能确定的时候完成 D．项目随时可能取消 2．项目是一系列（ D ）的活动和任务。
A．具有特定目标 B．具有明确开始和终止日期 C．消耗资源 D．以上皆是 3．下列属于项目的是（C ）。
A、生产线上生产汽车B、管理一个公司C、修建一座水库D、信息系统的维护二、多项选择题1．项目管理的基本特性有（ ABCDE ）。
A、目的性B、独特性C、普遍性D、创新性E、集成性 2．以下关于项目和日常运营说法正确的是（ ABCD ）。
A、项目中存在较多创新性、一次性的工作和活动B、日常运营中存在较多确定性、程序性、常规性和不断重复的工作或活动C、项目的环境是相对不确定的D、项目的组织形式多数是团队性的E、运营工作的组织管理模式主要是基于过程和活动的管理系统为主三、简答题1. 什么是项目？项目有哪些特点？答：项目是一个组织为实现既定的目标，在既定的资源和要求的约束下，为实现某种目的而相互联系的一次性工作任务。
项目具有目的性、独特性、一次性、制约性、过程性、不确定性、组织的临时性与开放性、成果的不可挽回性等特点。
2. 什么是项目管理？项目管理有哪些特点？答：项目管理是运用各种知识、技能、方法与工具，为满足或超越项目有关各方对项目的要求与期望所开展的各种计划、组织、领导和控制等方面的活动。
项目管理具有普遍性、目的性、独特性、创新性和集成性等特点。
四、论述题1. 项目与日常运营有哪些不同点？答：（1）根本目的和作用不同：项目的根本目的是为创造具有某种独特性的新成果。
但是运营的根本目的是通过使用特定项目的成果开展周而复始的日常工作从而获得相应的回报。
（2）结果和回收模式不同：项目工作的结果是人们获得的创新性成果，运营工作的结果是通过开展周而复始的运营活动不断获得收益并最终收回项目和运营投入。
（3）工作性质与内容不同：一般在日常运营中存在着大量的确定性、程序性、常规性和不断重复的工作或活动，而在项目中则存在较多创新性、一次性和具有不确定性的工作或活动。
工程流体力学习题课2
h
p0
14700 1.5m 9800
相当于液面下移1.5m，如图示虚构液面 则左侧：
P 1.2 2 70560 N 1 hc A 9800 2 1
hD1 1.2 2 3 J 12 hc c 2 1 3 0.11 3.11m 压力中心距A点：3.11－2＝1.11m hc A 3 1.2 2
解：以0－0断面为基准面，列1－1、2－2两断面的能量方程：
V12 p2 V22 0 z h 2g 2g p1
p1 p2
又由连续性方程：
Q 4 0.1 V1 1.42m / s 2 A1 3.14 0.3
V22 V12 z h 2g
6
习题课
6
工程流体力学
1.实际流体在等直管道中流动，在过流断面1， 2上有A，B，C点，则下面关系式成立的是：
A B √ C D
7
B
习题课
7
工程流体力学
2.如图所示管路系统中流体作实际运动，恒 定。圆管等直径，则下述判断正确的是：
A.该管路系统上点3和5的测压管水头相等；
√
B.该管路系统上点3的测压管水头与点4的测压管水头相等； C.该管路系统上点1的 动水压强p1=g水· h1； D.该管路系统上点1和8 的动水压强p1=p8=pa。
10
习题课
10
工程流体力学
• 5.水流一定方向应该是（
• A、从高处向低处流；
）
• B、从压强大处向压强小处流；
• C、从流速大的地方向流速小的地方流； • D、从单位重量流体机械能高的地方向低的地方 流。
人工智能课后习题第2章 参考答案
第2章知识表示方法参考答案2.8设有如下语句，请用相应的谓词公式分别把他们表示出来：(1)有的人喜欢梅花，有的人喜欢菊花，有的人既喜欢梅花又喜欢菊花。
解：定义谓词P(x)：x是人L(x,y)：x喜欢y其中，y的个体域是{梅花，菊花}。
将知识用谓词表示为：(∃x )(P(x)→L(x, 梅花)∨L(x, 菊花)∨L(x, 梅花)∧L(x, 菊花))(2) 有人每天下午都去打篮球。
解：定义谓词P(x)：x是人B(x)：x打篮球A(y)：y是下午将知识用谓词表示为：(∃x )(∀y) (A(y)→B(x)∧P(x))(3)新型计算机速度又快，存储容量又大。
解：定义谓词NC(x)：x是新型计算机F(x)：x速度快B(x)：x容量大将知识用谓词表示为：(∀x) (NC(x)→F(x)∧B(x))(4) 不是每个计算机系的学生都喜欢在计算机上编程序。
解：定义谓词S(x)：x是计算机系学生L(x, pragramming)：x喜欢编程序U(x,computer)：x使用计算机将知识用谓词表示为：¬(∀x) (S(x)→L(x, pragramming)∧U(x,computer))(5)凡是喜欢编程序的人都喜欢计算机。
解：定义谓词P(x)：x是人L(x, y)：x喜欢y将知识用谓词表示为：(∀x) (P(x)∧L(x,pragramming)→L(x, computer))2.9用谓词表示法求解机器人摞积木问题。
设机器人有一只机械手，要处理的世界有一张桌子，桌上可堆放若干相同的方积木块。
机械手有4个操作积木的典型动作：从桌上拣起一块积木；将手中的积木放到桌之上；在积木上再摞上一块积木；从积木上面拣起一块积木。
积木世界的布局如下图所示。
图机器人摞积木问题解：(1) 先定义描述状态的谓词CLEAR(x)：积木x上面是空的。
ON(x, y)：积木x在积木y的上面。
ONTABLE(x)：积木x在桌子上。
HOLDING(x)：机械手抓住x。
人教版高中语文必修4 第一单元 第2课 雷雨 习题练习二(附答案))
人教版高中语文必修4 第一单元第2课雷雨习题练习二（附答案）一、选择题1.下面有关戏剧常识的表述，不恰当的一项是()A．中国的现代戏剧主要指20世纪以来从西方传入的话剧、歌剧、舞剧等，话剧是其中的主体。
我们常说的戏剧鉴赏主要指中国现代、当代戏剧和外国戏剧的鉴赏。
B．戏剧必须有集中、尖锐的矛盾冲突。
根据矛盾冲突的性质，戏剧又可分为悲剧、喜剧和正剧。
《雷雨》属于悲剧。
C．戏剧语言是戏剧的灵魂，它包括人物语言和舞台说明。
人物语言也叫台词，包括对话、独白、旁白等。
好的台词总是以最少的语言表达最丰富的内容。
D．舞台说明，又称舞台提示，是剧作者根据演出需要，提供给导演和演员的说明性的文字。
这些说明对推动、展开戏剧情节发展有一定的作用，而与刻画人物性格关系不大。
2.下列有关文学常识的表述，错误的一项是()A．曹禺是我国现代著名剧作家，主要代表作品有《雷雨》《日出》《北京人》《屈原》等。
B．《雷雨》这部剧作为我们揭示了一个封建资产阶级大家庭成员之间的种种矛盾，主要人物有周朴园、蘩漪、周萍、四凤、鲁侍萍。
C．戏剧是一种在舞台上表演的综合艺术，它借助文学、表演、音乐、舞蹈、美术等艺术手段来塑造人物形象，揭示社会矛盾，反映社会生活。
D．戏剧按题材所涉及的内容可分为现代剧(如《雷雨》)、历史剧(如《王昭君》)。
3.下列词语中,加线字的注音完全正确的一项是()A．离间(jiàn)伺候(cì)纺绸(fáng)侍从(shì)B．怜悯(mǐn)弥补(mí) 江堤(dī)谛听(tì)C．沉吟(yín) 惊愕(è) 固执(zhi) 本分(fèn)D．仆人(pū) 烦躁(zào) 雪茄(jiā)郁热(yù)4.下列词语中没有错别字的一项是()A．境况窟窿一帆风顺委屈求全B．家俱啼哭自寻烦恼平白无辜C．敲诈拖延生性固执与心不忍D．习惯拜望虚情假意软硬兼施5.下列句子空缺处应填的词语，最恰当的一项是( )①我只想看看他，他是我生的孩子。
计算物理课后部分习题答案2
1.1 Show that the error in the n th-order Lagrange interpolation scheme isbounded bywhere γn = max[| f (n +1)(x )|], for x ∈ [x 0, xn ])()(1n x f 10n x x x x x x ---+=∆ ）（）！（）（γ设γn=max[|f（n+1）|]当x 在区间[x 0，x n ]，h 是h i =x i+1-x i 中的最大的一个，Eq （2.9）中的γ可以用γn 代替 要证明()hn x f n14)(+≤∆γn+1须证)1(4)!1()())((110+≤+---+n h n x x x x x x n n（1）首先我们考虑该式子前项,我们假设x 在x k 与x k+1之间 则)!1()())(())(()!1()())((11010+-----=+---+n x x x x x x x x x x n x x x x x x n k k n （2）又因为式子中的4))((21h x x x x k k ≤--+运用“缩放法”可得（2）式[])1(4!)!1(4)!()!1(11+≤+-+≤++n h n n h k n k n n )1(41+=+n h n既得证（1）式成立∴1)1(4)(++≤∆nn hnxfγ2.2Write a program that implements the Lagrange interpolation scheme directly. Test it by evaluating f (0.3) and f (0.5) from the data taken from theerror function with f (0.0) = 0, f (0.4) =0.428 392, f (0.8) = 0.742 101, f (1.2) = 0.910 314, and f (1.6) = 0.970 348. Examine the accuracy of the interpolation by comparing the results obtained from the interpolation with the exact values f (0.3) = 0.328 627 and f (0.5) = 0.520 500public class a {public static void main(String[] args) {double xi[]={0,0.4,0.8,1.2,1.6};double fi[]={0,0.428392,0.742101,0.910314,0.970348};double x1=0.3;double f1=aitken(x1,xi,fi);double x2=0.5;double f2=aitken(x2,xi,fi);System.out.println("interpolated value:"+f1);System.out.println("interpolated value:"+f2);}//Methed to carry out the Aitken recursions.public static double aitken(double x,double xi[],double fi[]){int n =xi.length-1;double ft[]=(double[]) fi.clone();for (int i=0; i<n; ++i) {for(int j=0; j<n-i; ++j) {ft[j]=(x-xi[j])/(xi[i+j+1]-xi[j])*ft[j+1]+(x-xi[i+j+1])/(xi[j]-xi[i+ j+1])*ft[j];}}return ft[0];}}运行结果：interpolated value:0.32934490136718747interpolated value:0.5199387451171875与the exact values f(0.3)=0.328627 and f(0.5)=0.520500对比2.3The Newton interpolation is another popular interpolation scheme thatadopts the polynomialShow that this polynomial is equivalent to that of the Lagrange interpolation and the coefficients c j here are recursivelygiven byWrite a subprogram that creates all c j with given xi and fi/*** 输入各个x和f的值及检验值xi；* 定义系数ci和牛顿插值结果p；* 引入函数aitken1和aitken2；* 输出所求系数ci在给出x和f值下的各个数值；* 根据所求牛顿插值与拉格朗日插值比较并输出比较结果；* *定义函数aitken1* *引入定义ci，t,T,y；* *for循环求出各个系数ci的值；* *返回ci值；* *定义函数aitken2* *引入定义p，g；* *for循环求出牛顿插值结果P；* *返回p[j]值；*/public class sun3 {public static void main (String argv[]){double x[]={0,0.5,1.0,1.5,2.0};//输入x的各个值；double f[]={1.000000,0.938470,0.765198,0.511828,0.223891};//输入f的各个值；double xi=0.9;//输入所需求的x值；double[] h = new double[5];double[] ci = aitken1 (x,f);double pi = aitken2 (xi,x,ci);double fi=0.807473;for(int i=0;i<5;i++)System.out.println("All c with given x and f：c"+i+"="+ci[i]);//输出ci 的各个值；System.out.println("Lagrange interpolation:"+fi);//输出fi的值；System.out.println("Newton interpolation:"+pi);//输出p近似值；System.out.println("We can see that the Lagrange interpolation"+fi +" is equivalent to the Newton interpolation"+pi);}//Method to carry out the aitken1 recursions.--引入 aitken1 函数；public static double[] aitken1(double x[],double f[]){int n=x.length-1;int i,j;double[] h = new double[n+1];double[] t = new double[n+1];double[] T = new double[n+1];double[] y = new double[n+1];//引入 h t T ；for( i=0;i<n+1;i++){for( j=1;j<i+1;j++){h[0]=f[0];t[0]=1;T[0]=0;y[0]=1;T[j]=T[j-1]-t[j-1]*h[j-1];t[j]=t[j-1]*(x[i]-x[j-1]);y[j]=y[j-1]*(x[i]-x[j-1]);}h[i]=(f[i]+T[i])/y[i];}//求 h 的各个值；return h;//返回各个 h 的值；}//Method to carry out the ba recursions.--引入aitken2 函数；public static double aitken2 (double xi,double x[],double ci[]){ int n=x.length-1;double[] p = new double[n+1];double[] g = new double[n+1];double[] v = new double[n+1];int i,j;p[0]=ci[0];v[0]=0;for( j=1;j<n+1;j++){for( i=1;i<j+1;i++){g[0]=1;g[i]=g[i-1]*(xi-x[i-1]);}v[j]=ci[i-1]*g[i-1];p[j]=p[j-1]+v[j];}return p[4];}}输出结果：All c with given x and f：c0=1.0All c with given x and f：c1=-0.12305999999999995All c with given x and f：c2=-0.22348400000000002All c with given x and f：c3=0.04219199999999986All c with given x and f：c4=0.009258000000000247Lagrange interpolation:0.807473Newton interpolation:0.8074728208000002We can see that the Lagrange interpolation0.807473 is equivalent to the Newton interpolation0.80747282080000022.4Show that the coefficients in the Newton interpolation, defined in Exercise 2.3, can be cast into divided differences recursively aswhere ai = fi are the discrete data and a0...i = ci are the coefficients inthe Newton interpolation. Write a subprogram that creates ci in this way.Apply this subprogram to create another subprogram that evaluates theinterpolated value from the nested expression of the polynomialUse the values of the Bessel function in Section 2.1 to test the program/*第四题 pn=c0+c1*(x-x0)+c2*(x-x0)*(x-x1)+.........public class Newton4 {public static void main(String[] args) {double pn;pn=0;double xi[]={0,0.5,1,1.5,2};double fi[]={1,0.938470,0.765198,0.511828,0.223891};double x=0.9;int n=xi.length-1;double dx=1;double ft[]={1,0.938470,0.765198,0.511828,0.223891};System.out.println("value of c0: "+1.0);for(int i=0;i<n;i++){for(int j=0;j<n-i;j++){ft[j]=(ft[j+1]-fi[0])/(xi[j+i+1]-xi[i]);}fi=ft;System.out.println("value of ci :"+fi[0]);for(int k=0;k<=i;k++){dx *= (x-xi[k]);}pn+=(fi[0]*dx);}pn=pn+1;System.out.println("value of pn: "+pn);}}输出结果如下：value of c0: 1.0value of ci :-0.12305999999999995value of ci :-0.22348400000000002value of ci :0.24304000000000003value of ci :-1.1915873333333336value of pn: 0.8143025768125697结果和书上的 Aitken 数值相近。
计算机组成原理之习题课2.
22．某计算机的I/O设备采用异步串行传送方式传送字符信息， 字符信息的格式为：一位起始位、七位数据位、一位检验位、 一位停止位。若要求每秒钟传送480个字符，那么该I/O设备 的数据传送速率应为____bps(位／秒)。 A．1200 B．4800 C．9600 答案：B 23．以串行接口对ASCII码进行传送，带一位奇校验位和两位停 止位，当波特率为9600波特时，字符传送率为____字符/秒 A．960 B． 1371 C. 480 答案：A 25．I/O与主机交换信息的方式中，中断方式的特点是____。 A．CPU与设备串行工作，传送与主程序串行工作 B．CPU与设备并行工作，传送与主程序串行工作 C．CPU与设备并行工作，传送与主程序并行工作 答案：B
可以按每个存取周期结束响应DM A请求的方案（本来就 是如此）
10. 一个DMA接口可采用周期窃取方式把字符传送到存储器，它支 持的最大批量为400个字节。若存取周期为0.2s，每处理一次中断需 5s ，现有的字符设备的传输率为9600 bps。假设字符之间的传输是 无间隙的，试问DMA方式每秒因数据传输占用处理器多少时间，如 果完全采用中断方式，又需占处理器多少时间? (忽略预处理所需的 时间)。
若采用中断方式，每秒因数据传输占用处理器的时间是 5 s ×1200 ＝ 6000 s
Hale Waihona Puke 2. 设磁盘存储器转速为3000转/分，分8个扇区，每扇区存储1KB， 主存与磁盘存储器传送的宽度为16b。假设一条指令最长执行时 间是25s，是否可采用一条指令执行结束时响应DMA请求的方 案，为什么? 若不行，应采取什么方案？
解： 磁盘的转速为 3000／60＝50 r／s 则磁盘每秒可传送 1KB× 8 × 50＝400KB 信息 若采用DMA方式，每秒需有： (400 KB／2B) = 200K 次DMA请求，即： ( 1／200K ) = 5 s 有一次DMA请求。 故，不能采用一条指令执行结束时响应DMA请求的方案。
2丁香结 教材课后习题答案
第2课丁香结
1.朗读课文。
说说作者是从哪几个方面描写丁香的。
〔答案大家找〕作者从色彩、形貌、气味、姿态等方面描写丁香,赋予丁香灵动幽雅、洁白无瑕、可爱芬芳的品格。
2.读下面的句子,联系上下文回答括号里的问题。
(1)〔答案大家找〕“积雪”指白丁香花。
从“香气”看出来的。
(2)〔答案大家找〕雨中丁香的特点是鲜润妩媚,自信无畏。
雨中的丁香朦胧绰约,线条模糊,颜色柔和,着了水滴的丁香花格外妩媚,不禁让作者赞同古人常将丁香和微雨联系在一起的写法。
3.丁香结引发了作者对人生怎样的思考?结合生活实际,谈谈你的理解。
〔答案大家找〕“丁香结”象征生活中化解不开的烦恼、愁怨。
结是解不完的,人生的问题也是解不完的,生命给了你丁香的芬芳,同时也给了你幽怨的“丁香结”,作者认为这是一种常态,如果没有困难,反而缺少起伏,太平淡无味了。
现实生活中,我们如果遇到困难了,也要像作者一样,勇于面对困难,相信自己一定能战胜困难。
北师大版数学必修二课件：习题课2
(组)求得各系数,进而求出圆的方程.
探究一
探究二
探究三
探究四
探究五
一题多解
变式训练1 已知圆C与y轴相切,圆心C在直线l1:x-3y=0上,且圆C在
直线l2:x-y=0上截得的弦长为 2 7, 求圆C的方程.
解:因为圆心C在直线l1:x-3y=0上,
(8)圆的常用几何性质.
①圆心在圆的任一条弦的垂直平分线上.
②圆上异于直径端点的点与直径的两端点连线垂直.
③过切点且垂直于该切线的直线必过圆心.
做一做1 已知x2+y2-2x+y+k=0是圆的方程,则实数k的取值范围是
(
)
A.(-∞,5)
C. -∞,
3
2
B. -∞,
D.
3
2
5
4
,+∞
解析:令D2+E2-4F=(-2)2+12-4k>0,得k <5.
即 x2+y2+2(1+λ)x+(λ-4)y+1+4λ=0.
∵此圆过原点,
1
∴1+4λ=0,λ=-4.
3
17
∴所求的圆的方程为 x2+y2+2x- 4 y=0.
①
(2)依题意可知当圆心在直线 2x+y+4=0 上时,所求的圆的面积
最小.
由(1)易得圆心坐标为 -(1 + ),-4
将其代入直线方程得-2(1+λ)-
x2+y2+Dx+Ey+F+λ(Ax+By+C)=0表示过直线l与圆C的两个交点的
建筑力学习题集2答案
《建筑力学》课程诊断性摸底案例题专业班级年级姓名学号摸底篇幅材料力学（内力）成绩重庆机电职业技术学院年月日材料力学部分1一、 画如下杆件体系的内力图（共54分）1.2.传动轴如图所示，主动轮A 输入功率P A=50kW ，从动轮B 、C 、D 输出功率分别为P B=P C=15kW ，P D=20kW ，轴的转速n =300r/min ，试绘出各段轴的扭矩图。
拉力绘在BCADM B3.外伸梁AB 承受荷载如图所示，作该梁的V —M 图。
CA解：1、求支反力kN8.3kN 2.7==B A R R 2、判断各段Q 、M 图形状：CA 和DB 段：q=0，V 图为水平线，M 图为斜直线。
AD 段：q<0，V 图为向下斜直线，M 图为上凸抛物线。
4. 用简便方法作图示各梁的剪力图和弯矩图。
mN ⋅637FaFqa 2qaqa 2qaqa 2/2A4kN 6kN·mF SM5. 设梁的剪力图如图所示，试作弯矩图和荷载图。
已知梁上没有作用集中力偶。
6kNF SMF二、应力强度及应变（共30分）1.图示空心圆截面杆，外径D ＝18mm ，内径d ＝15mm ，承受轴向荷载F ＝22kN 作用，材料的许用应力[σ]＝156MPa 。
试校核杆的强度。
()()()()[]不安全 156MPa MPa 283Pa 102830.015m m 180.0N102244622322>=⨯=-⨯⨯=-=ππσd D F2.图示结构中①杆是直径为32mm 的圆杆， ②杆为2×No .5槽钢。
材料均为Q 235钢，E =210GPa 。
求该拖架的许用荷载 [F ] 。
FBkN9.57][67.11][11==A F σkN9.57][}][]min{[][121===∴F F F F ，kN125][33.11][22==A F σAB 杆：4、确定许用荷载3、强度校核BC 杆：F⎩⎨⎧-==⇒⎩⎨⎧=-=--⇒⎪⎩⎪⎨⎧==∑∑F N F N F N N N F F 33.167.10sin 0cos 021121Y X αα2、计算各杆轴力3.图示一阶梯形截面杆，其弹性模量E=200GPa ，截面面积A I =300mm 2，A II =250mm 2,A III =200mm 2。
李凡长版 组合数学课后习题答案 习题2
第二章 容斥原理与鸽巢原理1、1到10000之间（不含两端）不能被4，5和7整除的整数有多少个？ 解 令A={1,2,3,…,10000}，则 |A|=10000.记A 1、A 2、A 3分别为在1与1000之间能被4,5和7整除的整数集合，则有：|A 1| = L 10000/4」=2500,|A 2| = L 10000/5」=2000,|A 3| = L 10000/7」=1428,于是A 1∩A 2 表示A 中能被4和5整除的数,即能被20 整除的数，其个数为| A 1∩A 2|=L 10000/20」=500；同理， | A 1∩A 3|=L 10000/28」=357,| A 2∩A 3|=L 10000/35」=285,A 1 ∩A 2 ∩ A 3 表示A 中能同时被4,5,7整除的数，即A 中能被4,5,7的最小公倍数lcm(4,5,6)=140整除的数，其个数为| A 1∩A 2∩A 3|=L 10000/140」= 71.由容斥原理知，A 中不能被4，5，7整除的整数个数为||321A A A ⋂⋂= |A| - (|A 1| + |A 2| +|A 3|) + (|A 1∩A 2| + |A 1∩A 3| +|A 3∩A 2|) - |A 1∩A 2∩A 3| = 51432、1到10000之间（不含两端）不能被4或5或7整除的整数有多少个？ 解 令A={1,2,3,…,10000}，记A 1、A 2、A 3分别为在1与1000之间能被4,5和7整除的整数集合，A 中不能被4，5，7整除的整数个数为||321A A A ⋃⋃ = |A| - ||321A A A ⋂⋂ - 2 = 10000 - L 10000/140」- 2 = 99273、1到10000之间（不含两端）能被4和5整除，但不能被7整除的整数有多少个？解 令A 1表示在1与10000之间能被4和5整除的整数集，A 2表示4和5整除，也能被7整除的整数集。
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无论是调频信号还是调相信号，它们的ω（t）和φ（t）都同时受到调变，其区别仅在于按调制信号规律线性变化的物理量不同，这个物理量在调相信号中是Δφ（t），在调频信号中是Δω（t）。
一般采用_包络_检波器解调普通调幅波信号，而采用__同步__检波器解调抑制载波的双边带或单边带信号。
锁相环路由_VCO__、__LPF__和__PD _组成，它的主要作用是消除频率误差。
AFC电路的作用是_______
调幅的就是用（调制）信号去控制（高频载波），使载波的（振幅）随（调制信号）大小变化而变化。
单项选择：
某单频调制的普通调幅波的最大振幅为10 v，最小振幅为6 v，则调幅系数m a为（）：A．0.6 B．0.4 C．0.25 D. 0.1
右图所示框图能实现何种功能？其中u s(t)= U s cosωc tcosΩt，u r(t)= U r cosωc t：（）
A. 振幅调制
B. 检波
C. 混频
D. 鉴频
属于频谱的非线性搬移过程的有（）:
A．振幅调制 B．调幅波的解调 C．混频 D．频率调制
在低电平调幅、小信号检波和混频中，非线性器件的较好特性是：（）
A．i=b0+b1u+b2u2+b3u3 B．i=b0+b1u+b3u3 C．i=b2u2 D. i=b3u3
二极管峰值包络检波器适用于哪种调幅波的解调（）
A．单边带调幅波B．抑制载波双边带调幅波
C．普通调幅波D．残留边带调幅波
用双踪示波器观察到右图所示的波形，此波形是哪种类型的调幅波（）
A．VSB B．SSB
C．DSB D．AM
一同步检波器，输入信号为u S =U S cos（ωC＋Ω）t，恢复载波u r =U r cos（ωC＋Δω）t，输出信号将产生（）。
A．振幅失真B．频率失真C．相位失真 D. 无失真
在波形上它的包络与调制信号形状完全相同的是（）A．AM B．DSB C．SSB D．VSB
AGC电路的作用是（）
A．维持工作频率稳定B．消除频率误差
C．使输出信号幅度保持恒定或仅在很小的范围内变化 D. 消除相位误差
问答：
高频已调波信号和本机振荡信号经过混频后，信号中包含哪些成分？如何取出需要的成分？
计算：
超外差式调幅广播接收机的组成框图如下图所示。
采用低中频，中频频率f I = 465kHz
(1)填出方框1和2的名称,并简述其功能。
(2)若接收台的频率为810kHz ，则本振频率f L = ?，已知语音信号的带宽为300~3400Hz ，试分别画出A 、B 和C 点处的频谱示意图（以单音频为例）。
345kHZ 或者1275kHz;
混频器，检波器
中心频率为810KHz,465KHz,及300~3400KHZ 。
有一调角波信号其表达式为：)2000cos 10102cos(10)(6t t t u ππ+⨯= （
V ） 试根据表达式分别确定：
⑴ 最大频偏。
⑵ 最大相移。
⑶ 信号带宽。
⑷ 信号在 100Ω电阻上的平均功率。
()()()44432000/1000Hz ()10cos 200010cos 2000()(1)210sin 2000210/,10Hz 2(2)10(3)2()2(101)1022kHz
(4)m m m m P S m rad S F t t
d t d t t dt dt
rad s f m rad
B f F πϕππϕωππωωππ
ϕΩ=∆=∆∆===-⨯∆∆=⨯∆==∆===∆+=+⨯=根据给定条件，可以看出，
，=，最大频偏最大相偏信号带宽因为调角波的功率就等()22
1050W 22(5)C L U R ===于载波功率，所以P 因为题中没给出调制信号的形式，因此无法判定它是FM 还是PM 信号。
某发射机输出级在负载R L =100Ω上的输出信号为u s (t)=8（1＋cos Ωt ）cos ωC t （V ），请问：
⑴ 该输出信号是什么已调信号？该信号的调制度m ＝？
⑵ 总的输出功率P av ＝？
⑶ 画出该已调信号的波形、频谱图并求频带宽度BW。