大二上学期练习册答案

合集下载

大学数学第二册详细答案汇总

大学数学第二册详细答案汇总

第一章 矩阵与行列式习题解答练习1.1 矩阵及其运算1. 已知线性变换x y y y x y y y x y y y 1123212331232235323=++=++=++⎧⎨⎪⎩⎪①②③, 求从变量x 1,x 2,x 3到变量y 1,y 2,y 3的线性变换。

解:由3x (1)–2×(2)得:4y 2–7y 3=3x 1–2x 2 ④ (3)–(2)得:y 2–2y 3=x 3–x 2 ⑤ (4)–4×(5)得:y 3=3x 1+2x 2–4x 3类似运算可得:y 1=–7x 1–4x 2+9x 3, y 2=6x 1+3x 2–7x 3 故由变量x 1,x 2,x 3到变量y 1,y 2,y 3的线性变换为y x x x y x x x y x x x112321233123749637324=--+=+-=+-⎧⎨⎪⎩⎪ 2. 已知两个线性变换x y y x y y y x y y y11321233123223245=+=-++=++⎧⎨⎪⎩⎪ y z z y z z y z z112213323323=-+=+=-+⎧⎨⎪⎩⎪ 求从z 1, z 2, z 3到x 1, x 2, x 3的线性变换。

解:将变换2代入变换1可得:x z z z x z z z x z z z1123212331236312491016=-++=-+=--+⎧⎨⎪⎩⎪3. 设A =111111111--⎛⎝⎫⎭⎪⎪⎪,B =123124051--⎛⎝ ⎫⎭⎪⎪⎪,求3AB –2A 及A T B 解:3AB –2A =3111111111--⎛⎝⎫⎭⎪⎪⎪123124051--⎛⎝ ⎫⎭⎪⎪⎪–2111111111--⎛⎝ ⎫⎭⎪⎪⎪ =3058056290-⎛⎝⎫⎭⎪⎪⎪–2111111111--⎛⎝ ⎫⎭⎪⎪⎪=----⎛⎝ ⎫⎭⎪⎪⎪21322217204292 A T B =111111111--⎛⎝⎫⎭⎪⎪⎪123124051--⎛⎝ ⎫⎭⎪⎪⎪=058056290-⎛⎝ ⎫⎭⎪⎪⎪ 4. 解:(1) (35, 6, 49)T , (2) (10) (3) ---⎛⎝⎫⎭⎪⎪⎪241236 (4) 6782056---⎛⎝ ⎫⎭⎪ (5) a x a x a x a x x a x x a x x 111222223332121213132323222+++++5. 设A =1213⎛⎝⎫⎭⎪,B =1012⎛⎝ ⎫⎭⎪,问 (1) AB =BA 吗? (2) (A +B )2=A 2+2AB +B 2吗? (3) (A +B )(A –B )=A 2–B 2吗? 解:AB =1213⎛⎝⎫⎭⎪1012⎛⎝ ⎫⎭⎪=3446⎛⎝ ⎫⎭⎪, BA =1012⎛⎝ ⎫⎭⎪1213⎛⎝ ⎫⎭⎪=1238⎛⎝ ⎫⎭⎪故 AB ≠BA 。

大物习题册答案及详解(山东理工大学大二上学期2020版)

大物习题册答案及详解(山东理工大学大二上学期2020版)
考点:无限大均匀带电平面的电场强度公式:E=σ/ε0,电场强度等于两个带电平行电板所产生的电场强度的矢量 和。(课本120页 例6-7 推导公式)
4.如图所示,一点电荷q位于正立方体的A角上,则通过侧面abcd的电通量Φe=q/24ε0
考点: 高斯定理公式 (课本118页 6-18) 解法:1.建立一正方体高斯面(补7个如图正方体),使A点位于正中心
考点:电势是一个与引进电荷无关,完全由电场自身的性质和相对位置决定的物理量。电场中某点电势的大小与零 电势点的选取有关。
2.在边长为a的正方体中心处放置一电量为Q的点电荷,设无穷远处为电势零点,则在一个侧面的中心处的电势为
(B)
(A)Q/4πε0a
(B)Q/2πε0a
(C)Q/πε0a
(D)Q/2√2πε0a
q/(1/r-1/r0)/4πε0
考点:电势的计算
解法:U=∫
r0 r
E·dr
=∫
r0 qdr r 4πε0r
2
=q/(1/r-1/r0)/4πε0
(课本122页
6-29b)
பைடு நூலகம்
3.一质量为m、电量为q的小球,在电_场__力__作__用下,从电势为U的a点移动到电势为零的b点,若已知小球在b点的 速率为Vb,则小球在a点的速率Va=√Vb2-2qU/m
②均匀带电球面内的电势UP2=Q/4πε0R(课本123页例6-8结论得), ③UP=UP1+UP2.
6.在带电量为-Q的点电荷A的静电场中,将另一带电量为q的点电荷B从a点移到b点,a、b两点距离点电荷A的距 离分别为r1和r2,如图所示,则移动过程中电场力做的功为(C) (A)-Q(1/r1-1/r2)/4πε0 (B)qQ(1/r1-1/r2)/4πε0 (C)-qQ(1/r1-1/r2)/4πε0 (D)-qQ/4πε0(r2-r1) 考点:电场力的功 解法:Aeab=q(UA-UB)=q(-Q/4πε0r1— -Q/4πε0r2)=-qQ(1/r1-1/r2)/4πε0 (课本123页 6-31)

大学物理学第二版上册课后答案

大学物理学第二版上册课后答案

大学物理学习题答案习题一答案 习题一1.1 简要回答下列问题:(1) 位移和路程有何区别在什么情况下二者的量值相等在什么情况下二者的量值不相等 (2) 平均速度和平均速率有何区别在什么情况下二者的量值相等(3) 瞬时速度和平均速度的关系和区别是什么瞬时速率和平均速率的关系和区别又是什么 (4) 质点的位矢方向不变,它是否一定做直线运动质点做直线运动,其位矢的方向是否一定保持不变(5) r ∆v 和r ∆v 有区别吗v ∆v 和v ∆v有区别吗0dv dt =v 和0d v dt=v 各代表什么运动 (6) 设质点的运动方程为:()x x t =,()y y t =,在计算质点的速度和加速度时,有人先求出r =drv dt= 及 22d r a dt =而求得结果;又有人先计算速度和加速度的分量,再合成求得结果,即v = 及 a =你认为两种方法哪一种正确两者区别何在(7) 如果一质点的加速度与时间的关系是线性的,那么,该质点的速度和位矢与时间的关系是否也是线性的(8) “物体做曲线运动时,速度方向一定在运动轨道的切线方向,法向分速度恒为零,因此其法向加速度也一定为零.”这种说法正确吗(9) 任意平面曲线运动的加速度的方向总指向曲线凹进那一侧,为什么(10) 质点沿圆周运动,且速率随时间均匀增大,n a 、t a 、a 三者的大小是否随时间改变 (11) 一个人在以恒定速度运动的火车上竖直向上抛出一石子,此石子能否落回他的手中如果石子抛出后,火车以恒定加速度前进,结果又如何一质点沿x 轴运动,坐标与时间的变化关系为224t t x -=,式中t x ,分别以m 、s 为单位,试计算:(1)在最初s 2内的位移、平均速度和s 2末的瞬时速度;(2)s 1末到s 3末的平均加速度;(3)s 3末的瞬时加速度。

解:(1) 最初s 2内的位移为为: (2)(0)000(/)x x x m s ∆=-=-= 最初s 2内的平均速度为: 00(/)2ave x v m s t ∆===∆ t 时刻的瞬时速度为:()44dxv t t dt==- s 2末的瞬时速度为:(2)4424/v m s =-⨯=-(2) s 1末到s 3末的平均加速度为:2(3)(1)804/22ave v v v a m s t ∆---====-∆ (3) s 3末的瞬时加速度为:2(44)4(/)dv d t a m s dt dt-===-。

大二英语上3册3单元课后题

大二英语上3册3单元课后题
4
improve “ The goal is to _________________ performance in schools that are not providing their students with tools for success,” said one government official. He admits, however, that he is having a hard time convincing faculty and teachers this plan will work.
9
other than [with negative or in questions]apart from; except除了 He claims not to own anything other than his home.他声称除了家他一无所有。 differently or different from; otherwise than 不同于;非 There is no suggestion that we are to take this other than literally. 并没有要我们不按字面去理解的意思。
14
over Truth is emphasized _______________ harmony. Students who have difficulty with following the school rules are assigned ____________ to perform maintenance jobs and lawn care for the school. The practice is not solely but also punitive _________________ serves to illustrate that the transgressor has separated him/herself from the community by their actions. The idea behind it is to earn __________________ acceptance by the group, and work back into the trust of the community.

大二大学英语教材答案

大二大学英语教材答案

大二大学英语教材答案Unit 1Reading Comprehension1. A2. B3. D4. C5. B6. CVocabulary1. preconceived2. assertion3. grasped4. menace5. enhance6. medium7. fluctuations8. reluctant9. incompatible10. predominantlyGrammar1. will be given2. was going; arrived3. had reached4. would have succeeded5. will have finished6. should readWritingDear Professor Smith,I am writing to inform you about the errors I noticed in the Unit 1 reading comprehension exercises of the English textbook for the second year.I believe it is important to address these issues and correct the mistakes for the benefit of the students.Firstly, in question 4, the correct answer should be "C" instead of "D." The information provided in the passage clearly supports this option. This mistake may cause confusion among the students and hinder their understanding of the text.Secondly, in question 5, the answer given as "C" is incorrect. The passage clearly states that the new study contradicts the widely accepted theories. Therefore, the correct answer should be "B." It is crucial to rectify this mistake to avoid misleading the students.Lastly, in question 6, the provided answer "C" is inaccurate. The passage describes the advantages of visual learning, not auditory learning. As such, option "A" should be considered as the correct answer. Correcting this error is necessary for students to accurately grasp the information presented in the passage.I hope you will take my concerns into consideration and make the necessary amendments to the textbook. This would greatly contribute to the quality of education and students' comprehension of the materials provided.Thank you for your attention to this matter. I look forward to your positive response and the improved version of the textbook.Yours sincerely,[Your Name]Note: The above answer is a sample response and may vary based on the actual content of the Unit 1 exercises in the given textbook.。

大二课后练习答案

大二课后练习答案

第一单元所有需要掌握的练习题P14选词填空• 1. favour• 2. make a distinction• 3. go with• 4. at an advantage• 5. stress• 6. energed•7. aggressive•8. solution•9. in terms of•10. be measuredP 16选词填空• 1. unnecessary• 2. irregular• 3. impatient• 4. incorrect• 5. illogical• 6. inefficientP16翻译题•Part A• 1. This poor diet is not enough to sustain the residents /dwellers/on the island.• 2.Nothing is to be gained by only memorizing vocabulary list if you want to get a higher mark in IELTS.• 3.In terms of natural resources this country is one of the poorest countries in Western Europe.• 4. Those who don’t adore/love power and influence would make life easy and convenient.• 5.Your way of learning will not only impact your competence/ability but also your grade/score.• 6. Those who don’t know how to make full use of college time are not at an employment advantage./at an unemployment disadvantage.[B]• 1. We decide to start /set out in fall so that the weather may favor our future one-month voyage.• 2.If the students take their marks /scores too seriously it will work against their learning.• 3.Day-dreaming, sleeping and using mobile phone in class are the signs of failure in exams for the students.• 4.To some degree, a farmer may feel as happy in his own way as a city millionaire. Happiness belongs to every human being.• 5. A young man with a sense of humor is much easier to attract girls’ attention.• 6. If you want to succeed in your career, you have to work very hard, for success often goes with diligence/hardworking.Page 17• 1. prolong 2. attitude 3. impact 4. adult 5. retire• 6. fun 7. intensive 8. temperament 9. life span•10. moderateTEXT BPage 24• 1. provided 2. in perspective• 3. stimulate 4. cancel out• 5. endangered 6. lose weight•7. Keep up 8. talked…into•9. keep off 10. Retain练习册P71-5 C B B C D 6-10 CCCBA 11-12 CBP42选词填空1. made a point of2. make a great differences3. For the sake of4. pays5. attached to6. tend to7. what’s more8. viewed as9. valued10. stay away fromP43A.1. Apart from telling me to take medicine in time2. rather than animals in the real sense3. doesn’t look as healthy as he used to4. Not surprising5.from the point of most students6.Instead, he tried to find a solution to the problemP44B.1.When he was studying abroad, he was especially attached to his motherland.2. Stay away from my daughter. I won’t allow her to associate with people likeyou.3. Be wary of those people around you who are always flattering you.4.For his daughter’s sake, he divorced again. He can’t stand his daughter beingill-treated.5. It is not what he said but what he did that counts.6. I believe that after you get acquainted with the city you’ll come to like it. P521.Deadline2.Isolated3.Chances4.Spinning5.Made fun of6.Drowned out7.At its best8.At her wit s’ end9.Depress10.Brightened练习册P19 1-5 DBABC 6-10 ADCBC 11-12 AC。

大学物理练习册(上册)答案

大学物理练习册(上册)答案

练习一 (第一章 质点运动学) 一、选择题 1、(D )2、(C )3、(D )4、(B )5、(D ) 二、填空题1、(1)A (2)1.186s(或4133-s) (3)0.67s (或32s ) 2、8m 10m3、(1)t e t t A βωβωωωβ-+-]sin 2cos )[(22 (2)ωπωπk +2( ,2,1,0=k ) 4、3/30Ct v + 400121Ct t v x ++ 5、(1)5m/s (2) 17m/s 三、计算题1、解:dxdvv dt dx dx dv x dt dv a ==+==262分离变数积分⎰⎰+=xvdx x vdv 020)62(得 )1(422x x v +=质点在任意位置处的速度为 )1(22x x v +=(由初始时刻的加速度大于零,可知速度的大小为非负)。

2、解:(1)第二秒内的位移为 m x x x 5.0)1()2(-=-=∆ 第二秒内的平均速度为s m txv /5.0-=∆∆= (2)t 时刻的速度为 269t t dtdxv -==第二秒末的瞬时速度为 s m s m s m v /6/26/292-=⨯-⨯=(3)令0692=-==t t dtdxv ,解得s t 5.1= 第二秒内的路程为 m x x x x s 25.2)5.1()2()1()5.1(=-+-=。

3、解:(1)由几何关系θθsin cos r y r x ==质点作匀速率圆周运动故dtd θω=,代入初始条件0=t 时0=θ,得 t 时刻t ωθ=,所以j y i x r+=)sin (cos j t i t rωω+=(2)速度为)cos sin (j t i t r dtrd v ωωω+-==加速度为)sin (cos 2j t i t r dt vd a ωωω+-==(3)r j t i t r dtv d a 22)sin (cos ωωωω-=+-==由此知加速度的方向与径矢的方向相反,即加速度的方向指向圆心。

哈金融大二上册统计学本科练习册答案

哈金融大二上册统计学本科练习册答案

第2章 数据的描述五、计算题1、随机抽取10个网络用户,得到他们的年龄数据如下(单位:周岁):19 16 29 25 20 2325362418(1)计算众数、中位数、上下四分位数和样本均值。

(2)计算年龄数据的极差和标准差。

(如果是小数,要求计算结果保留到小数点后两位。

)016181920232425252936125+2324=5.523.5210+1=8.25250.75290.252610+1=2.75180.25190.7518.7523.5e e M M M x x n =+===⨯+⨯==⨯+⨯===∑31解:先排序:、、、、、、、、、()(周岁)101的位次:(周岁)23上四分位数的位次:() 上四分位数Q (周岁)41下四分位数的位次:() 下四分位数Q (周岁)4(2()310.253616 5.8719x x R S n -=-==-∑周岁)(2)=20(周岁)=(周岁) 3、甲班40名同学平均身高为171cm ,标准差为10cm ,乙班身高资料如下表所示:要求:比较两班平均身高的代表性。

21556165111751818556820170.561118540(3190408.93=5.24%170.5)8.9310===5.85%==171xf x cm fx fcm fV V V x V x x σσσ+++∑====+++∑-∑==∑=<乙乙甲乙乙甲甲乙乙甲解:()()由于所以:乙班平均身高的代表性强。

;身高(cm ) 人数(人) 组中值x2()x x - 2()x x f - 150-160 6155 240.25 1441.5 160-170 11 165 30.25 332.75 170-180 18 175 20.25 364.5 180-190 5 185 210.25 1051.25 合计 40 - - 31904、在某品牌的节能灯泡中随机抽出430只进行测试,使用时数资料如下,计算使用时数的中位数、众数和均值。

  1. 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
  2. 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
  3. 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。

Unit1ⅠAssess-evaluate or estimate the nature or quality of Benefit-welfarePotential-possiblePrestige-statusDampen-reduce, subdueBe exempt from-not be affected or bound by, be excused fromCompensatory-related to the payment of compensationⅡMy First JobWhileI was waiting to university, I saw in a local newspaper a teaching post advertised at a school in a suburb of London about ten miles from where I lived. Being very short of money and wanting to do something useful, I applied, fearing as I did so, that without a degree and with on experience of teaching my chances of landing the job were slim.However, three days later a letter arrived,summon ing me to Croydon for an interview. It proved an awkward journey: a train to Croydon station; a ten-minute bus ride and then a walk at least a quarter of a mile. As a result, I arrived on a hot June morning too depressed to nervous.The school was a dreary, gabled Victorian house of red brick and with big staring sash-windows.The front garden wasa gravel square; four evergreen shrubs stood at each corner, where they struggled to survive the dust and fumes from a busy main road.It was clearly the headmaster himself that opened the door. He was short and rotund. He had a sandy-colored moustache, a freckled forehead and hardly any hair. He was wearing a tweed suit-one felt somehow he had always worn it-and across his ample stomach was looped a silver watch-chain.He looked at me with an air of surprised disapproval, as an colonel might look at a private whose bootlaces were undone. ”Ah, yes”he grunted. ”You’d better come inside.”The narrow sunless hall smelled unpleasantly of stale cabbage; the cream-printed walls had gone a dingy margarine color except where theywere scarred with ink marks; it was all silent. His study, including by the crumbs on the carpet, was also his dining room. On the mantelpiece there was a salt cellar and pepper-pot. “You’d better sit down,” he said, and proceeded to ask me a number of questions:what subject had I taken in my General School Certificate; how old was I; what games did I play; then fixing me suddenly with his bloodshot eyes, he asked me whether I thought games were a vital part of a boy’s education. I mumbled something about not attaching too much importance to them. He grunted. I had said the wrong thing. The headmaster and I obviously had singularly little in common.The school, he said, consisted of one class of twenty-four boys, ranging in age from seven to thirteen.I should have to teach all subjects except art, which he taught himself. Football and cricket were played in the Park, a mile away on Wednesday and Saturday afternoons.The teaching set-up appalled me. I should have to split the class up into three groups and teaching them in turn at three different levels; and I wasdismayed at the thought of teaching algebra and geometry-two subjects at which I had been completely incompetent at school.Worse perhaps was the idea of Saturday afternoon cricket. It was not so much having to tramp a mile along the dusty streets of Croydon, followed by a crocodile of small boys that I minded, but the fact that most of my friends would be enjoying leisure at that time.Isaid diffidently,”What would my salary be?”“Twelve pounds a week plus lunch.”B efore I could protest he got to his feet.” Now,” he said,” You’d better meet my wife. She’s the one who really runs this school.”This was the last straw. I was very young: the prospect of working under a woman constituted the ultimate indignity.Add: ceiling, girth, waist, distasteful, parade, admiralⅢ1.他们都认为他成功的可能性很小。

They all believed that he had a slim chance of success.2.我不知道她为何总带有一种闷闷不乐的神情。

I don’t know why she has an air ofsadness all the time.3.等到所有的同学都就座后,学生会主席才开始宣布野营的日程安排。

It was after all the students had taken their seats that the president of the students ’union proceeded to announce the camping itinerary. 4.胃是人体至关重要的器官,请善待之。

The stomach is a vital organ of the human body; please take good care of it.5.他认为总经理如此重视那些日常琐事是荒唐的。

He considered it ridiculous for the general manager to attach so much importance to those routine trifles.6.她的研究涉及多种语言和文化,富有挑战性。

Her study, which ranged over many languages and cultures, was full of challenge.7.根据安排,全体工作人员轮流值晚班。

As is scheduled, all members of staff take turns to do late duty.8.想到要远离父母独立生活,她深感不安。

She was greatly upset at the thought of leaving her parents and living on her own in a remote area.9.对于她是否胜任这项工作我们不甚担心,我们更担心她的健康问题。

相关文档
最新文档