文档库 最新最全的文档下载
当前位置:文档库 › 第5章课后习题答案

第5章课后习题答案

第五章(1)

一、选择题

D C D A C A C D D C D D D

二、判断题

Y Y N N Y Y Y Y

三、阅读分析题

1、pos=pos+k neg=neg+k print pos+neg

2、I=j or j=0 a(I,j)=a(I-1,j)+a(I-1,j-1) print

第五章(2)

一、选择题

A D

B A D B A A B B B D D B A

二、判断题

Y Y N N N N N N Y N

三、阅读分析题

1、1000timer1.enabled=true 0 x\3600 x mod 60

2、n=3 x=42 y=9

第五章(3)

一、选择题

D B D D D B C D A

二、判断题

Y Y Y Y Y

三、阅读分析题

1、2 5 9

2、a b(n-k+1) b(n-k+1)

3、n=1 z=4

n=2 z=7

n=3 z=10

第五章(4)

一、选择题

B C B A B B B A

二、阅读分析题

1、"文本文件(*.txt)/*.txt" commondialog1.filename

2、form1.hide

第五章(5)

一、选择题

D B A A D A

二、阅读分析题

1、y=5 a=5

y=15 a=10

y=30 a=15

2、for input not(eof())

3、input #1,x write #2,y

高中人教版英语必修五课本答案

教材练习答案及听力原文 Unit 1 WARMING UP ?Answers: 1 Archimedes, Ancient Greek (287-21 2 BC) He was a mathematician. He found that if you put an object into water the water pushes the object up. It rises and partly floats. The force of the water pushing it up is the same as the weight of the object. 2 Charles Darwin, British (1808-1882) The Origin of Species was published in 1859. It explained how plants and animals had changed over time to fit in with a changing environment. At the time it was published it was very controversial. Many people believed the Bible when it said that God made the first two people (Adam and Eve) and that all other people came from these two. Darwin’s book showed that people had developed from apes instead. So this caused a lot of ar gument between religious and scientific people. However Darwin’s idea became very influential and is still accepted today. 3 Thomas Newcomen, British (1663-1729) He improved the first steam pump built by Thomas Savery in 1698 and turned it into a steam engine for taking water out of mines in 1712. James Watt improved it still further in the 1770s turning it into the first modern steam engine used on the railways. 4 Gregor Mendel, Czech (1822-1884) He grew pea plants and developed ideas on heredity and inherited characteristics. He concentrated on cross-fertilising pea plants and analyzing the results. Between 1856-1863 he grew 28,000 pea plants. He examined seven kinds of seed and plant characteristics and developed some laws of inheritance. The first is that inheritance factors do not combine but are passed to the next generation intact. Second, he found that each partner gives half the inherited factors to the young. Third, some of these factors show up in the offspring (and so are dominant). The other factors are masked by the dominant ones (and so are recessive). 5 Marie Curie, Polish and French (1867-1934) She was born in Poland and came to study in France in 1891 and she lived there for the rest of her life. In 1898 she discovered radium. She received two Nobel prizes, one (with Pierre Curie) for physics (1903) and one for chemistry (1911). She is the only person to have been so honoured. On the death of her husband she took over his job at the Sorbonne in Paris. Her work on radioactivity and the discovery of radium meant that she began a new scientific area of research. She was the first woman to receive a Nobel Prize and the first woman to teach at the Sorbonne. 6 Thomas Edison, American (1847-1931) He was already an inventor of other electrical devices (phonograph, electric light bulb) when in 1882 he designed a system for providing New York with electricity from a central power station. This was a tremendous achievement, which had previously been thought impossible.

Linux第5章课后习题答案

Linux思考题5 1.fork()和clone()二者之间的区别是什么? 答:fork创建一个进程时,子进程只是完全复制父进程的资源,复制出来的子进程有自己的task_struct结构和pid,但却复制父进程其它所有的资源。 通过fork创建子进程,需要将上面描述的每种资源都复制一个副本。fork()调用执行一次返回两个值,对于父进程,fork函数返回子程序的进程号,而对于子程序,fork函数则返回零,这就是一个函数返回两次的本质。在fork 之后,子进程和父进程都会继续执行fork调用之后的指令。 系统调用fork()和vfork()是无参数的,而clone()则带有参数。fork()是全部复制,vfork()是共享内存,而clone()是则可以将父进程资源有选择地复制给子进程,而没有复制的数据结构则通过指针的复制让子进程共享,具体要复制哪些资源给子进程,由参数列表中的clone_flags来决定。另外,clone()返回的是子进程的pid。 2.什么是进程?什么是线程?Linux系统中的进程有那些状态?如何获取系统 中各进程的状态? 答:进程是指在系统中正在运行的一个应用程序;线程是系统分配处理器时间资源的基本单元,或者说进程之内独立执行的一个单元。对于操作系统而言,其调度单元是线程。一个进程至少包括一个线程,通常将该线程称为主线程。一个进程从主线程的执行开始进而创建一个或多个附加线程,就是所谓基于多线程的多任务。 Linux系统中的进程状态有:TASK_RUNNING(运行状态),TASK_INTERRUPTIBLE(可中断睡眠状态),TASK_UNINTERRUPTIBLE(不可中断的睡眠状态),TASK_STOPPED(暂停状态),TASK_NONINTERACTIVE(不可交互睡眠状态),TASK_DEAD(死亡状态),EXIT_ZOMBIE(僵死进程),EXIT_DEAD(僵死撤销状态) ps 查看静态的进程信息 可以使用man 来查看 ps 的使用参数以下是几个常使用到得, a 显示当前终端的所有进程信息 u 使用以用户为主的格式输出进程信息 x 显示当前用户在所有终端下的进程信息 -e 显示系统内的所有进程 # ps 只显示当前用户打开的进程 ]# ps aux 显示系统中所有进程信息 3.Linux系统中进程有哪两种模式?各有何特点? 答:用户进程和系统进程, 用户进程就是用户自己打开的应用程序,可有可无。 系统进程即是内核进程,是维持操作系统正常工作自动生成的,关闭系统进程会产生不可预知的结果。 4.Linux系统中进程控制块的作用是什么?它进程有何关系?

大学英语精读5_课后答案

U1 Vocabulary work 一 1.given 2.at a glance 3.fluency 4.Given 5.hopefully 6.For its part 7.define 8.looked him up 9.no good 10.quoted, context 11.guidance 12.immediate 13.disgust

https://www.wendangku.net/doc/824401489.html,e across 15.put into practice 16.scope 二 1.washed his hands of 2.given 3.putting…into practice 4.was confronted with 5.countering 6.were reduced to eating 7.at a glance 8.took refuge in 9.less practicable 10.countered 11.dedication 12.in disgust

14.for their part 15.gave up 三 1.Without suitable entertainment, these young people often get bored and take refuge in drinking and taking drugs. 2.The school washed its hands of the students’ beha vior during the spring recess. 3.The innocent girl was reduced to crying at his cruel remarks. 4.Many difficult words are out of the scope of his learner’s dictionary. 5.The thief admitted his guilt as soon as he was confronted with evidence. 6.The incident should be viewed in the wider context of the political turmoil of that time. 四 1.has come down 2.came to

高中数学必修五综合测试题(卷) 含答案解析

绝密★启用前 高中数学必修五综合考试卷 第I卷(选择题) 一、单选题 1.数列的一个通项公式是() A.B. C.D. 2.不等式的解集是() A.B.C.D. 3.若变量满足,则的最小值是() A.B.C.D.4 4.在实数等比数列{a n}中,a2,a6是方程x2-34x+64=0的两根,则a4等于( ) A.8B.-8C.±8D.以上都不对 5.己知数列为正项等比数列,且,则()A.1B.2C.3D.4 6.数列 1111 1,2,3,4, 24816 L前n项的和为() A. 2 1 22 n n n + +B. 2 1 1 22 n n n + -++C. 2 1 22 n n n + -+D. 2 1 1 22 n n n + - -+ 7.若的三边长成公差为的等差数列,最大角的正弦值为,则这个三角形的面积为() A.B.C.D. 8.在△ABC中,已知,则B等于( ) A.30°B.60°C.30°或150°D.60°或120° 9.下列命题中正确的是( ) A.a>b?ac2>bc2B.a>b?a2>b2 C.a>b?a3>b3D.a2>b2?a>b 10.满足条件,的的个数是( ) A.1个B.2个C.无数个D.不存在

11.已知函数满足:则应满足()A.B.C.D. 12.已知数列{a n}是公差为2的等差数列,且成等比数列,则为()A.-2B.-3C.2D.3 13.等差数列的前10项和,则等于() A.3 B.6 C.9 D.10 14.等差数列的前项和分别为,若,则的值为()A.B.C.D. 第II卷(非选择题) 二、填空题 15.已知为等差数列,且-2=-1,=0,则公差= 16.在中,,,面积为,则边长=_________. 17.已知中,,,,则面积为_________. 18.若数列的前n项和,则的通项公式____________ 19.直线下方的平面区域用不等式表示为________________. 20.函数的最小值是_____________. 21.已知,且,则的最小值是______. 三、解答题 22.解一元二次不等式 (1)(2) 23.△的角、、的对边分别是、、。 (1)求边上的中线的长;

高一必修5解三角形练习题及答案

第一章 解三角形 一、选择题 1.在A B C ?中,a =03,30;c C == (4) 则可求得角045A =的是( ) A .(1)、(2)、(4) B .(1)、(3)、(4) C .(2)、(3) D .(2)、(4) 2.在ABC ?中,根据下列条件解三角形,其中有两个解的是( ) A .10=b , 45=A , 70=C B .60=a ,48=c , 60=B C .14=a ,16=b , 45=A D . 7=a ,5=b , 80=A 3.在ABC ?中,若, 45=C , 30=B ,则( ) A ; B C D 4.在△ABC ,则cos C 的值为( ) A. D. 5.如果满足 60=∠ABC ,12=AC ,k BC =的△ABC 恰有一个,那么k 的取值范围是( ) A B .120≤

三、解答题 11. 已知在ABC ?中,cos A = ,,,a b c 分别是角,,A B C 所对的边. (Ⅰ)求tan 2A ; (Ⅱ)若sin()2 B π += ,c =求ABC ?的面积. 解: 12. 在△ABC 中,c b a ,,分别为角A 、B 、C 的对边,5 82 22bc b c a - =-,a =3, △ABC 的面积为6, D 为△ABC 内任一点,点D 到三边距离之和为d 。 ⑴求角A 的正弦值; ⑵求边b 、c ; ⑶求d 的取值范围 解:

第五章课后部分习题答案

第五章课后部分习题答案

第五章课后习题答案 二、计算题 1.(1)该会计混淆了资本的5天使用成本与一年的使用成本。这两个成本是不可比的,必须将时间长度转化一致才可比较。 (2)%94.14610 15360%21%2=-?- (3)如果公司决定不获得现金折扣,在到 期日之前支付是毫无道理的。若是购货后30天付款,而非15天付款,则年利息成本可下降至 %73.3610 30360%21%2=-?- 2.放弃10天内付款的现金折扣成本=%7.3610 30360%21%2=-?- 放弃20天内付款的现金折扣成本=%4.3620 30360%11%1=-?- (1)因为银行的贷款利率为15%,低于放弃现金折扣成本,所以该公司不应放弃现金折扣,并且放弃10天内付款的现金折扣成本大于放弃20天内付款的成本,所以应在第10天付款。 (2)因为短期投资收益率比放弃折扣的代价高,所以应在第30天付款。

3.(1)外购: TC=3600×9.8+1440=36720(元) 自制: TC=825+10×3600=36825(元) 不考虑缺货的情况下,自制成本高,外购成本低。 (2)外购的经济订货批量 每年订货次数=3600/360=10(次) 交货期内的平均每天需要量=3600/360=10(件) 如果延迟交货1天,则交货期为10+1=11(天),交货期内的需要量=11×10=110(件),概率为0.25 如果延迟交货2天,则交货期为10+2=12(天),交货期内的需要量=12×10=120(件),概率为0.1 如果延迟交货3天,则交货期为10+3=13(天),交货期内的需要量=13×10=130(件),概率为0.05 ①保险储备B=0时, 再订货点R=10×10=100(件) S=(110-100)×0.25+(120-100)×

现代大学英语精读5(第二版)课后答案

Lesson 1 Vocabulary 1. Manhood:the state of being human 2. White lie:harmless or trivial lie,esp.one told in order to avoid hurting sb. 3. black sheep:person regarded as a disgrace or a failure by other members of his family or group 4. To upset: to defeat 5. Affirmation:stating sth.as truth firmly and forcefully 6. To strain: to make the greatest possible effort 7. Off base: mistaken 8. (a) want (of) : lack of 9. Ringing cry: rallying call Paragraph 1. The job of arousing manhood within a people that have been taught for so many centuries that they are nobody is not easy. It is no easy job to educate a people who have been told over centuries that they were inferior and of no importance to see that they are humans, the same as any other people. 2. Psychological freedom, a firm sense of self-esteem, is the most powerful weapon against the long night of physical slavery. If you break the mental shackles imposed on you by white supremacists, if you really respect yourself, thinking that you are a Man, equal to anyone else, you will be able to take part in the struggle against racial discrimination. 3. The Negro will only be free when he reaches down to the inner depths of his own being and signs with the pen and ink of assertive manhood his own emancipation proclamation. The liberation of mind can only be achieved by the Negro himself/herself. Only when a negro is fully convinced that he/she is a Man/Woman and is not inferior to anyone else, can he/she throw off the manacles of self-abnegation and become free. 4. Power at its best is love implementing the demands of justice, and justice at its best is power correcting everything that stands against love. Power in its best form of function is the carrying out of the demands of justice with love and justice in the best form of function is the overcoming of everything standing in the way of love with power. ability and 5. At that time economic status was considered the measure of the individual’s talents. At that time, the way to evaluate how capable and resourceful a person was to see how much money he had made (or how wealthy he was). 6. …the absence of worldly goods indicated a want of industrious habits and moral fiber. A person was poor because he was lazy and not hard-working and lacked a sense of right and wrong. 7. It is not the work of slaves driven to their tasks either by the task, by the taskmaster, or by animal necessity. This kind of work cannot be done by slaves who work because the work has to be done, because

高中数学必修五测试题含答案

高一数学月考试题 一.选择题(本大题共12小题,每小题5分,共60分) 1.已知数列{a n }中,21=a ,*11()2 n n a a n N +=+∈,则101a 的值为 ( ) A .49 B .50 C .51 D .52 211,两数的等比中项是( ) A .1 B .1- C .1± D .12 3.在三角形ABC 中,如果()()3a b c b c a bc +++-=,那么A 等于( ) A .030 B .060 C .0120 D .0150 4.在⊿ABC 中,B C b c cos cos =,则此三角形为 ( ) A . 直角三角形; B. 等腰直角三角形 C. 等腰三角形 D. 等腰或直角三角形 5.已知{}n a 是等差数列,且a 2+ a 3+ a 10+ a 11=48,则a 6+ a 7= ( ) A .12 B .16 C .20 D .24 6.在各项均为正数的等比数列 {}n b 中,若783b b ?=, 则31 32log log b b ++……314log b +等于( ) (A) 5 (B) 6 (C) 7 (D)8 7.已知b a ρρ,满足:a ρ=3,b ρ=2,b a ρρ+=4,则b a ρρ-=( ) A B C .3 D 10 8.一个等比数列}{n a 的前n 项和为48,前2n 项和为60,则前3n 项和为( ) A 、63 B 、108 C 、75 D 、83 9.数列{a n }满足a 1=1,a n +1=2a n +1(n ∈N +),那么a 4的值为( ). A .4 B .8 C .15 D .31 10.已知△ABC 中,∠A =60°,a =6,b =4,那么满足条件的△ABC 的形状大小 ( ). A .有一种情形 B .有两种情形

人教版生物生物必修二教材课后习题答案

人教版生物生物必修二教材课后习题答案 第1章遗传因子的发现 第1节《孟德尔的豌豆杂交实验(一)》 (一)问题探讨 1. 粉色。因为按照融合遗传的观点,双亲遗传物质在子代体内混合,子代呈现双亲的中介性状,即红色和白色的混合色——粉色。 2. 提示:此问题是开放性问题,目的是引导学生观察、分析身边的生物遗传现象,学生通过对遗传实例的分析,辨析融合遗传观点是否正确。有些学生可能举出的实例是多个遗传因子控制生物性状的现象(如人体的高度等),从而产生诸多疑惑,教师对此可以不做过多的解释。只要引导学生能认真思索,积极探讨,投入学习状态即可。 (二)实验 1. 与每个小组的实验结果相比,全班实验的总结果更接近预期的结果,即彩球组合类型数量比DD ∶Dd ∶dd=1∶2∶1,彩球代表的显性与隐性类型的数值比为3∶1。因为实验个体数量越大,越接近统计规律。 如果孟德尔当时只统计10株豌豆杂交的结果,则很难正确地解释性状分离现象,因为实验统计的样本数目足够多,是孟德尔能够正确分析实验结果的前提条件之一。当对10株豌豆的个体做统计时,会出现较大的误差。 2. 模拟实验的结果与孟德尔的假说是相吻合的。因为甲、乙小桶内的彩球代表孟德尔实验中的雌、雄配子,从两个桶内分别随机抓取一个彩球进行组合,实际上模拟雌、雄配子的随机组合,统计的数量也足够大,出现了3∶1的结果。但证明某一假说还需实验验证。 (三)技能训练 提示:将获得的紫色花连续几代自交,即将每次自交后代的紫色花选育再进行自交,直至自交后代不再出现白色花为止。 (四)旁栏思考题 不会。因为满足孟德尔实验条件之一是雌、雄配子结合机会相等,即任何一个雄配子(或雌配子)与任何一个雌配子(或雄配子)的结合机会相等,这样才能出现3∶1的性状分离比。 (五)练习 基础题1.B。2.B。 3. (1)在F1水稻细胞中含有一个控制合成支链淀粉的遗传因子和一个控制合成直链淀粉的遗传因子。在F1形成配子时,两个遗传因子分离,分别进入不同配子中,含支链淀粉遗传因子的配子合成支链淀粉,遇碘变橙红色;含直链淀粉遗传因子的配子合成直链淀粉,遇碘变蓝黑色,其比例为1∶1。 (2)孟德尔的分离定律。即在F1形成配子时,成对的遗传因子发生分离,分离后的遗传因子分别进入不同的配子中。(3)2。 4. (1)白色;黑色。 (2)性状分离;白毛羊为杂合子,杂合子在自交时会产生性状分离现象。 拓展题 1. (1)将被鉴定的栗色公马与多匹白色母马配种,这样可在一个季节里产生多匹杂交后代。 (2)杂交后代可能有两种结果:一是杂交后代全部为栗色马,此结果说明被鉴定的栗色公马很可能是纯合子;二是杂交后代中既有白色马,又有栗色马,此结果说明被鉴定的栗色公马为杂合子。 2. 提示:选择适宜的实验材料是确保实验成功的条件之一。孟德尔在遗传杂交实验中,曾使用多种植物如豌豆、玉米、山柳菊做杂交实验,其中豌豆的杂交实验最为成功,因此发现了遗传的基本规律。这是因为豌豆具有适于研究杂交实验的特点,例如,豌豆严格自花受粉,在自然状态下是纯种,这样确保了通过杂交实验可以获得真正的杂种;豌豆花大,易于做人工

大学英语精读第五册课后习题答案

第一课 Vocabulary work 一 1. given 2. at a glance 3. fluency 4. Given 5. hopefully 7. define 8. looked him up 9. no good 10. quoted, context 11. guidance 12. immediate 13. disgust 14. come across 15. put into practice 16. scope 二 1. washed his hands of 2. given 3. putting…into practice 4. was confronted with 5. countering 6. were reduced to eating 7. at a glance 8. took refuge in 9. less practicable 10. countered 11. dedication 12. in disgust 13. relied on 14. for their part 15. gave up 三 1. Without suitable entertainment, these young people often get bored and take refuge in drinking and taking drugs. 2. The school washed its hands of the students’ behavior during the sp ring recess. 3. The innocent girl was reduced to crying at his cruel remarks. 4. Many difficult words are out of the scope of his learner’s dictionary. 5. The thief admitted his guilt as soon as he was confronted with evidence. 6. The incident should be viewed in the wider context of the political turmoil of that time. 四 1. has come down 2. came to 3. comes out 4. come up with 5. come in 6. came across 7. has come about 8. come off 9. come to 10. give up 11. was given back 12. gave away 13. gave out 14. give in 15. gives off/out cloze 1. express 2. both 3. intended 4. still 5. where 6. personal 7. of 8. them 9. make 10. before 11. still 12. before 13. fluent 14. while 15. enough 16. on 17. in 18. In 19. Find 20. Who 21. carefully 22. to

高二英语必修5测试题及答案

高二英语必修(5)测试试题 注意事项: 1. 本试卷由选择题和非选择题两大部分组成。选择题包括第一部分和 第二部分;非选择题为第三部分。 2. 1—65题涂在答题卡上。A涂A; B涂B; C涂C; D涂D; E涂AB; F涂AC; G涂AD. 第一部分:英语知识运用(共四节,满分55分) 第一节:语音知识(共5小题;每小题1分,满分5分) 从每小题所给的A、B、C、D四个选项中,找出所给单词的正确读音,并在 答题卡上将该选项涂黑。 1. A. /???? B./???? C./ ???? D. /???? A.? B. ? C.? D. ? 2. contribute A./k?n tr?b?t/ B. /k?n tr?bj?:t/ C./k?n tr?b?t/ D./k ?n tr?bj?:t/ remind A.? B.?? C.? D.?? A./sep? B. ?r?t/ C./s?pr? D.??r?t/ 第二节:情景对话(共5小题;每小题1分,满分5分) 根据对话情景和内容,从对话后所给的选项中选出能填入每一个空白处的最 佳答案,并在答题卡上将该选项涂黑。 Jack: Hi, Frank Frank:Hi, Jack Jack:: 6___ Frank:Yes, I have some books to read, but I can do it later Jack:I want you to do me a favor. Frank:go ahead 7_________ Jack:Professor Smith is coming this afternoon, I am expected to meet him at the airport, but I have an important meeting to go to Frank:I can do it for you. 8 Jack:He’s about your age, in his early thirties. Tall and hand some Frank:9______ Jack:Oh, about three o’clock, He is taking flight number 231 from

现代大学英语精读5_第1.2.3.5课后paraphrase和翻译答案

Lesson1 1.The job of arousing manhood within a people that have been taught for so many centuries that they are nobody is not easy. It is no easy job to educate a people who have been told over centuries that they were inferior and of no importance to see that they are humans, the same as any other people. 2.Psychological freedom, a firm sense of self-esteem, is the most powerful weapon against the long night of physical slavery. If you break the mental shackles imposed on you by white supremacists, if you really respect yourself, thinking that you are a Man, equal to anyone else, you will be able to take part in the struggle against racial discrimination. 3.The Negro will only be free when he reaches down to the inner depths of his own being and signs with the pen and ink of assertive manhood his own emancipation proclamation. The liberation of mind can only be achieved by the Negro himself/herself. Only when he/she is fully convinced that he/she is a Man/Woman and is not inferior to anyone else, can he/she throw off the manacles of self-abnegation and become free. 4.Power at its best is love implementing the demands of justice, and justice at its best is power correcting everything that stands against love. Power in the best form of function is the carrying out of the demands of justice with love and justice in the best form of function is the overcoming of everything standing in the way of love with power. 5.At that time economic status was considered the measure of the individual’s ability and talents. At that time, the way to evaluate how capable and resourceful a person was to see how much money he had made (or how wealthy he was). 6.…the absence of worldly goods indicated a want of industrious habits and moral fiber. A person was poor because he was lazy and not hard-working and lacked a sense of right and wrong. 7.It is not the work of slaves driven to their tasks either by the task, by the taskmaster, or by animal necessity. This kind of work cannot be done by slaves who work because the work has to be done, because they are forced to work by slave-drivers or because they need to work in order to be fed and clothed. 8.…when the unjust measurement of human worth on the scale of dollars is eliminated. …when the unfair practice of judging human value by the amount of money a person has is done away with. 9.He who hates does not know God, but he who has love has the key that unlocks the door to the meaning of ultimate reality. Those who harbor hate in their hearts cannot grasp the teachings of God. Only those who have love can enjoy the ultimate happiness in Heaven. 10.Let us be dissatisfied until America will no longer have a high blood pressure of creeds and an anemia of deeds. Let us be dissatisfied until America no longer only talk about racial equality but is unwilling or reluctant to take action to end such evil practice as racial discrimination.

高中数学必修五测试题含答案

高一数学月考试题 1.选择题(本大题共 12 小题,每小题 5 分,共 60 分) 1.已知数列{a n }中, a 1 2 , a n 1 a n 1 2 (n N ) , 则 a 101 的值为 ( ) A .49 B .50 C .51 D .52 2. 2 + 1 与 2 - 1,两数的等比中项是( ) A .1 B . - 1 C . ± 1 D . 1 2 3.在三角形 ABC 中,如果 a b c b c a 3bc ,那么 A 等于( ) A . 30 B . 60 C .120 0 D .150 0 4.在⊿ABC 中, c cos C b cos B ,则此三角形为 ( ) A . 直角三角形; B. 等腰直角三角形 C. 等腰三角形 D. 等腰或直角三角形 5.已知 { a n } 是等差数列,且 a 2+ a 3+ a 10 + a 11 =48,则 a 6+ a 7= ( ) A .12 B .16 C .20 D .24 6.在各项均为正数的等比数列b n 中,若b 7b 83, 则 log 3 b 2 …… log 3 b 14 等于( ) (A) 5 (B) 6 (C) 7 (D)8 7.已知 a , b 满足: a =3, b =2, a b =4,则 a b =( ) A . 3 B . 5 C .3 D 10 8.一个等比数列{a n } 的前 n 项和为 48,前 2n 项和为 60,则前 3n 项和为( ) A 、63 B 、108 C 、75 D 、83 9.数列{a n }满足 a 1=1,a n +1 =2a n +1(n ∈N + ),那么 a 4 的值为( ). A .4 B .8 C .15 D .31 10.已知△ABC 中,∠A =60°,a = 6 ,b =4,那么满足条件的△ABC 的形状大 小 ( ). * 0 r r r r r r r r

相关文档