我感激不尽已知数轴上点A和点B分别表示互为相反数的两个数a,b(a),并且A,B两点的距离是6,求a,b的值.已知数轴上

　　我从来没有这样激动过
　　我读小学6年级了,回顾以前的小学生活,有多少值得回忆的事情呀!
　　记得,在四年级的时候,我写了一篇《我的爸爸》的作文.在作文课上,老师说：“这是蔡慧同学的作文,如果她能仔细修改一下,可以投稿.”当全班同学的目光一齐投向我时,我激动极了,心里像正在燃烧的烈火……我紧握拳头,决心把这篇作文好好修改,寄出去.回家后,我同家人商量着如何修改,等我修改完后,我郑重的在信封上写清了邮寄地址,邮了出去.一期、两期、三期……一连好几期的报纸都没见我的作文发表,渐渐地,我失望了.在国庆节开学的第一天,我收到了一封信,是报社邮来的,是我成功了?还是我失败了?我的手不停的在颤动,我打开了信封,一看,里面装的还是我的作文,我失望了,心里像比什么东西揪一下都难受.忽然,我在作文后面发现了两行字,是报社对作文的批语：文章有发表价值,你可以请老师辅导一下,将作文删一些字.我不再失望!经过老师的帮助和我的努力,我再次将作文邮了出去,可又被退了回来.让我另投别处,我鼻子一酸,流出了泪.在当天的班队会上,老师说：“我希望同学们,再学习方面,不管遇到多大的挫折和打击,都不要灰心,要继续努力.”我偷偷的打开作文仔细的看了看,原来,我把老师说的可以删去几个与事无关的人物词或人物,以为成了删词,我一删,就删的只剩下一位人物了,把内容搞的太空荡了.找到了问题,又经过我精心修改.这次,几位老师看了后都说：“不错,可以投稿!”于是,我再次投了出去.可喜的一天终于来了,我的作文发表了,当我把报纸拿在手里时,我是多么激动,我从来没有这样激动过,我激动的不知用什么语言来表达我内心的激动,只是“噢噢”的喊着,眼里含着的泪花不由的掉了下来,也许,这就是表达吧!
　　直到现在,我一想起这件事,心里依旧很激动.

你这几句不是标准的中式越南语吗?
Hy vọng chúng tôi đang cùng nhau mãi mãi!（đang可能写错别字）
希望我们能永远在一起!
Hy vọng bạn sẽ thêm hiểu biết và khoan dung!
希望你会有更多的理解和宽容!
Hy vọng ngày mai sẽ tốt hơn!
希望明天会更好!
个人意见仅供参考!

I want to widen my knowledge,improve my own development,perfect myself and make my life become more wonderful.

回眸小学四年级,那年,懂事听话的我居然不能专心听讲了!
老师在滔滔不绝地讲课,可我的思绪却随着墙角的那只蚂蚁而飘向远方：它在干什么呢?玩耍?找食物?还是迷路了?没错,就是这么一点小小地变化都会使我分神.
窗外的大树会使我想到小鸟的窠巢；天上的云朵会是我想到梦里的天国；就连地上的面包屑也会使我想到小昆虫会不会把它搬走?
就这样,由于没有听老师讲的内容,我的成绩就像溜滑滑梯一样直线下降.我的举动很快引起了老师的注意,随即下达了"召见家长”的“号令”.不行,不能见家长,否则我还能吃得消么?于是乎,第二天我就送去了“家长有事来不了”的消息.这件事就这样不了了之了……
尽管叫家长的事解决了,可成绩始终是我身边的一大隐患.班主任更像一枚定时炸弹,见到她我就像老鼠见了猫似的——躲着走,因为指不定哪天她就要问及我家长的事情.
纸包不住火,抱有侥幸心理的永远不会成功.一个下雨天,妈妈来学校接我,正好与老师遇见了.唉,是福不是祸,是祸躲不过.要打要骂,悉听尊便!
踩着清浅的水洼,帆布鞋被微微泯湿了边.阵阵微风带来刺骨的寒意.一滴雨滴从雨伞的边缘凸显出来,映出一片小小的世界,“吧嗒”一声碎了……
家里的一切还是老样子：软软的拖鞋,香喷喷的饭菜.饭后,我依旧回卧室写作业,妈妈依旧陪在我身旁……
我吐人觉得自己好可笑,面对失败、挫折,我从来没有奋斗过、拼搏过.而是抱有一种自甘堕落的心态.于是那一刻我站起来了,我告诉自己：“我一定行!”
或许,对于这件事,我并没有失败,我只是在人生的道路上遇到了一座高山,无法攀越而已.可是最终,我为自己开辟了一条道路,攀上了这座高峰!

取点该物质,加氢氧化钠溶液,稍加热后有难闻的氨气味道应该有氨根离子．加氯化钡溶液,有沉淀,加盐酸溶液沉淀不溶解应该是硫酸根．判断硫酸根就不是那么绝对啊!

就是 the Internet,注意要加定冠词 the,而且 I 一定要大写.
Internet Explorer 是“因特网探索者”,是用来看网页的浏览器的名字,不是指网络本身.

You won't bite back when bitten by a dog.

It's bad news.
Now the food safety is important for us.
They also spend money on saveing.
It should be doing something to help the family.

1.have you(句中有never表否定)
2.didn't you(together表示有很多人,用复数)
3.do they(陈述部分的主语为these,those,nobody,eveybody,everything,somebody等,简略句的主语用they)
4.didn't they
5.will you例Don't forget it,will you?(不用Won't you?)祈使句用will you
6.can you( 陈述部分谓语是think,suppose,believe,expect等,且主语为第一人称或第二人称时,简略句肯定或否定语气与主句对应,而主语和时态却与从句一致)
7.is there( 当陈述部分的主语含有no,never,hardly,little,seldom few等词,这部分按否定处理,为简略句应用肯定式)
8.is he

to touch sb.
to move sb.
I was deeply moved/touched by it.
It moved/touched me deeply.

A small fish in the ocean

化学能转化为内能,内能转化为机械能

世上谁能无有过,莫为小事动干戈,和与人交受众敬,百忍堂中有太和.
为自己写下一页历史,让我们共创一本书,让我们人生更显光彩.

ab连锁率10% bc20% 这个知道吧 则AB10% Ab=aB=（100%-10%-10%）/2=40% 同理BC=10% Bc=bC=40% 符合系数=实际双交换/理论双交换 理论双脚换=10%*20%=2% 所以实际双交换=0.4*2%=0.8% 可能产生的有 亲代型A B C 34.6% 二分之一100%减其他的 a b c 34.6% 单交换a B C 5% 二分之一AB交换率 A b c 5% 单交换A B c 10% 二分之一BC交换率 a b C 10% 双交换a B c 0.4% 二分之一双交换率 A b C 0.4% 这个写的很清楚了 如果看不懂 就去看看书 说明你基本概念没懂 第二题就是第一题的反过来,就是问你亲代型的二分之一有多少 还是类似的方法,还按我这样列表 你自己算算吧.打字好累的

如果谓语动词是实义动词就用副词,如果是系动词就用形容词,如
He is as tall as you .
He works as carefully as you .( work是实义动词,故用副词carefully)
He is as careful as you .
如果不明白,请再问；如果对你有所帮助,
请点击本页面中的“选为满意回答”按钮,

The biggest mistake that a mortal may make is to exchange his own health for other mere worldly possessions.
The biggest mistake that a mortal may make is to bater his own health for other external things that are not physically connected with him.

诗歌或儿歌吧(只是建议)
200~300字,反应现在的交通安全状况与自己的期望,如果不是很正式,诙谐一点也可.
什么级别的征文?市级?校级?
如果用记叙文,就需要很深的功底,可论文又不新颖.那就记叙文吧,写得突出,如不是很正式,记得要诙谐!切记!因为参赛作文写这类的基本都是很严肃的,功底又很高,如果你没足厚的底,就不能正面硬拼,只能出奇制胜,但不能太偏题(不然除非你运气绝好)

命令只能指挥人,榜样却能吸引人（威.亚历山大）
一个榜样胜过书上二十条教诲（罗.阿谢姆）
启事在教诲,成事在榜样（法国）
教诲是条漫长的道路,榜样是条捷径（塞内加）
优良的示范是最好的说服（英国）
好人的榜样是看得见的哲理（英国）
好榜样就像把许多人召集到教堂去的钟声一样（丹麦）
村中有个好嫂嫂,满巷姑娘齐学好
用道德的示范来造就一个人,显然比用法律一约束他更有价值（希腊）
模范比教训更有力量（希腊）
一个好的榜样,就是最好的宣传（英国）
极少有几个生活的榜样是完美和纯粹的（蒙田）
青年的思想愈被范例的力量所激励,就愈会发出强烈的光辉（法捷耶夫）
榜样的力量是无穷的（科·达勒维耶）

1
Can animals be made to work for us ? Some scientists think that one day animals may be t____ to do a number of simple jobs .They s____ that in a film or on TV we may see elephants , monkeys ,dogs ,bears ,or other animals doing a lot of things .If you w_____ carefully , you may find that those animals are given something to eat in return for d____ them . The scientists say that many d_____ animals may be taught to do a number of simple jobs if they will get something to eat .
Of course, as we know , dogs can be used to guard a house ,and elephants can be used to do some heavy j___ . And we can also teach animals to work in f____ .Apes ,for example have b____ used in America to help make cars and scientists b_____ that these monkeys may one day get in crops and e____ drive trains .
KEYS:1
taught , say , watch , doing , different , jobs , factories , been , believe , even .
2
Do you have a pet? Are you i_____ in taking care of animals? Girls and boys who like animals may want to study to be animal doctors.They are often c_____“vets ”. Many of them work in animal h_____. Others may work on farms or at a z_____. Some study animal diseases and try to find w_____ to keep the animals from getting i______. They do studies in m_____ for animals.Vets listen to an animals’s h______. They check its ears, eyes, mouth and blood. They o______ on animals when they need to. They may give the animals shots(注射) and tell the pets’ o_____ what food is best.
1.______interested____2.___called______3._hospital_s______ 4.______zoo_____ 5.____what______
6._____ill____7._______museum___8.___hearts_____9. ___operate________ 10._____owners____
KEYS:2
interested ,called , hospitals , zoo , ways ,
ill , medicine , heart , operate , owners .
3
I was walking down the street one day , I s______ a small bag on the ground . I picked it up and opened it to see w_______ I could find out the owner’s name . There was n_______ inside it except some dollars and a picture of a woman and a young girl about twelve years old . I put the photo back and took the bag to the police station . Before I left , the policeman wrote down my name and my a_______ . He thought the owner might want to thank me .
That evening I went to have dinner with my aunt and uncle . They had also asked a young woman to have dinner with us . Her face was familiar , but I couldn’t r_______ where I had seen her . D________ our talk , the young woman happened to say that she had l_______ her bag that afternoon . All at once I remembered w_______ I had seen her . She was the young girl in the photo . though she looked now much o______ than the girl in the picture . She was very s_______ , of course , when I told her about the bag . After dinner we went to the police station and got back her bag . The policeman said to me , “It’s a wonderful thing . You found not only the bag , but also the owner of the bag .”
1___saw______ 2________whether__ 3___________nothing__ 4___address_________ 5____remember_________ 6______During___ 7________lost_____ 8____where_________ 9____older________ 10_____surprised________
KEYS:3
saw , whether , nothing , address , remember ,
During , lost , where , older , surprised .
4
Only mother love is true love. It gives e_________ everything all his life.
When you are still a baby, mother takes good care of you as much as possible. In your waking hours she always holds you in her arms. When you are ill, she stops her work right now to look after you day and n__________ and forgets about herself. When you are growing up day by day, she feels very happy.
When you are old e__________ to go to school, mother still looks after you all the t_______ . On cold winter days, she always tells you to p_______ on more clothes. She always stands in the wind waiting for you back from school every day. When you hurry to leave home for school with little b_________ . She always feels worried about you at home. She u________ knows about you study and spend much money on your school things. When you do well at school , you will see the brightest s__________ on her face. Mother can do everything for you day after day.
Mother is always ready to give everything she has to her children, not to receive. What true love that is in the w________ ! We will r____________ Mother Love for ever!
1___everybody______ 2_______night___ 3________enough___ 4________time__ 5 ___put_______
6___busy______ 7_____usually_____ 8________smile___ 9_________world_ 10 __remember________
KEYS:4
1. everyone / everybody 2. night 3. enough 4. time 5. put
6. breakfast 7. usually 8. smile 9. world 10.remember
5
Seumas Mcsporran is a very b____ man. He is 60 years old and he has thirteen jobs. He is a postman , a policeman ,a fireman , a taxi driver , a school-bus driver , a boatman ,an ambulance man , an accountant , a petrol attendant , a barman , and an undertaker .Also , he and his wife , Margaret , have a shop and a small hotel.Seumas l_____ and works on the island of Gigha in the west of Scotland. Only 120 people live on Gigha but in s_____ 150 tourists come by b_____ every day.Every weekday Seumas gets up at six and makes b_____ for the hotel guests. At eight he drives the island’s children to s_____ . At nine he collects the post from the boat and delivers it to all the houses on the island. He also delivers the beer to the island’s only pub. Then he helps Margaret in the s_____ .He says：“Margaret likes being busy,too.We n_____ have holidays and we don’t like w_____ television. In the evening Margaret makes supper and I do the accounts. At ten we have a glass of wine and then we go to bed. P_____ our life isn’t very exciting, but we like it.”
1.______busy____ 2 _lives__________ 3 _______search_____ 4 __________bus__ 5 ______breakfast_____
6.____school______ 7 _____sea______ 8 ______never______ 9 _________watch___ 10 ___Perhaps________
KEYS:5
1. busy 2. lives 3. summer 4. boat 5. breakfast 6. school 7. shop 8. never 9. watching 10. Perhaps
6
Tim spent in a bookshop can be enjoyable . If you go to a good s________ , no assistant will come near to you and say , “Can I h______ you ?” You needn’t buy a________ you don’t want . You may try to find out where the book you want is . But if you w_______ , the assistant will lead you there and then he will go away . It seems that he is not interested i_____ selling any books at all .
There is a story which t_______ us about a good shop . A medical student found a very useful book in a shop , but it is too expensive for him to b______ . He couldn’t get it from the library , e_______ . So every afternoon he went there to r______ a little at a time . One day , however , he couldn’t find the book from its usual place and was leaving when he saw an assistant signing to him . To his s________ , the assistant pointed to the book in a corner , “I put it there so as not to be sold out .”said the assistant . Then he let the student go on with his reading .
KEYS:6
store , help , anything , want , in ,
tells , buy , either , read , surprise .

淘宝网 我自己去找了`

would you mind helping me book tickets for my colleagues during my two-week off(12-Nov to 23-Nov I would be very grateful if you can help me with this matter!

拜托出题了
……

1 It ,to do
2 It ,to eat
3 Then he ride a /his bike to a bus station .

Do you agree with "there is no motivation left for me to do it" or "I will try,miracle might happen"?
(introduction)
People are who they are because of their emotions.One of which is desperation,and the other is despair.When people are desperate,they will try whatever is there and hope for the best,while when people are in despair,they try nothing.The two statements in question are clear questions that one would ask in each emotional stage.I,however,do not agree with the saying "there is no motivation left for me to do it."
(argument 1)
Firstly,the prime motivation should always be for ourselves.We are doing it because it would make our life better.I suppose the condition is as so,otherwise the question in title would have no meaning.Thus,when we are doing it for ourselves,we always have the reason.
(argument 2)
Secondly,one never know what might happen.Instead of wait and lose,why not try and lose?In the end,when one looks back,one would say to himself:"I tried".Rather than regret:"I could have tried."
(argument 3)
Thirdly,miracles do happen.Although scientifically speaking,miracles are just fruits of hard work,but one never know whether his work will be successful.So one should always try first,surprises happen everyday.The god of luckiness doesn't mind place his hand on you when he have placed his hand on many others already.
(conclusion)
People are weak at times.Thus,the holes in humanity is revealed.The only way to cover up that hole,is to use courage.When the Allies were losing in World War Two,people were desperate.But what kept them moving?It is courage.The courage to believe.To believe that we will win one day,and the bad shall never conquor us.

这些都是一些标准问题,查一些资料,都是说常用的.外贸书籍上都有,可以去查查看看,不难的!只不过你这太多了.耽误时间!自己努力吧.

6
B
A
1)有理数:0,2/3,-1.1,³√8.无理数:π,-√2,√17
2) 0+2/3+(-1.1)-(-√1/9-1/10)=0
3) -√2<-1.1<0<2/3<³√8<π<√17

Free direct phone calls ,Convenience service counter,Please Check your money on the Spot

设武汉长江大桥铁路桥长X米,由题可得：
5X+197=9772
5X=9575
X=1915
设武汉长江大桥公路桥长Y米,由题可得：
3Y-421=4589
3Y=5010
Y=1670
答：（1）武汉长江大桥铁路桥长1975米,{2}武汉长江大桥公路桥长1670米.

设A,B,C速度分别为Va,Vb,Vc,物体通过AB段与BC段所用时间相同,都设为t
因为AB平均速度=位移/时间=(Va+Vb)/2=L1/t (1)
BC平均速度=位移/时间=(Vb+Vc)/2=L2/t (2)
AC平均速度=位移/时间=(Va+Vc)/2=(L1+L2)/2t (3)
(1)-(2),得到(Va-Vc)/2=(L1-L2)/t (4)
(4)+(3),得到Va=(3L1-L2)/2t,Vb=(L1+L2)/2t
因为Vb^2-Va^2=2aL1
a=(Vb^2-Va^2)/2L1=[((L1^2+2L1L2+L2^2)/4t^2-(9L1^2-6L1L2+L2^2)/4t^2]/2L1
=(8L1L2-8L1^2)/8t^2L1=(L2-L1)/t^2
因为O点物体静止
所以OA=Va^2/2a=[(3L1-L2)^2/4t^2]/[2(L1-L2)/t^2]
=(3L1-L2)^2/8(L1-L2)

鱼亲，对我的回答满意的话，就给个好评吧。如果还有不清楚的地方，可以跟我继续交流哦。为啥？这出自岑文本的奉述飞白书势。你没学过？哪有为什么，你读一读全诗就知道了。锦绣是金鱼我知道，到你觉得老师会出这么简单的题？你如果不想找骂就滚好吧，比我老师还凶，我试试不就行了么...

不好意思啊.
不过我可以给你提供几个成语#17..
希望可以给你带来帮助!
冰清玉洁、洁白如玉、香清色雅、冰雕玉琢……

志志向

只有三篇作文
1、请以“告别”为题,600字记叙性文章.
2、请你以“感谢——”为题,600字.
3、“黑板上的记忆”,依旧是600字.
好了.楼主,就只有三篇作文.给我分吧.

If I were God I would do all the things I'd like to do.
I would never go to work or pay attention to some jerk
I would jump from every mountain.
I would sail the seven seas
I would fly up in the sky
I would see all the things I never see
I would always be with you and make all your dreams come true
I would fill your days with laughter
I would live a million years
We'd be happy ever after
They would never see our tears
Guess how wonderful it would be
how wonderful it would be

第一题 ：21-4/3-4/15-4/35-4/63-4/99-4/143-4/195-4/255
=21-4/(1*3)-4/(3*5)-4/(5*7)-4/(7*9)-4/(9*11)-4/(11*13)-4/(13*15)-4/(15*17)
=21-(2/1-2/3)-(2/3-2/5)-(2/5-2/7)-(2/7-2/9)-(2/9-2/11)-(2/11-2/13)-(2/13-2/15)-(2/15-2/17)
=21-2/1+2/3-2/3+2/5-2/5+2/7-2/7+2/9-2/9+2/11-2/11+2/13-2/13+2/15-2/15+2/17
=21-2+2/17=19又2/17
第二题：设19=a,97=b
原式等于（a/b+101a/101b)/(1010101a/1010101b)=(a/b+a/b)/(a/b)=2
第三题 ：设礼物数为n
第一位入场的取的1+0.1*（n-1),剩余n-1-0.1*(n-1)=0.9*（n-1)
第二位入场的取的2+0.1*（0.9*（n-1）-2）
1+0.1*（n-1)=2+0.1*（0.9*（n-1）-2）
10+n-1=20+0.9*（n-1)-2
n=9+0.9n-0.9
0.1n=8.1
n=81
因此第一位入场的取的1+0.1*（n-1)=1+0.1*（81-1）=1+0.1*80=1+8=9
因此得到礼物的人数为81/9=9人,礼物的总数为81件

老师上课要我们用：……………………（乱写十五个成语）造句
读书笔记：……………………（乱写十五个成语）

语法讲一千遍过后的结果往往不是学生更加明白而是更加的糊涂.
语法的学习首先要知道什么时候用这个语法项目以及在什么地方用这个语法项目.
时态往往和说话人的主观表达意图有很大的关系,如进行时会让你的描述生动形象,完成时富含深层次的含义甚至于感情,一般式往往只是毫无目的的简单直陈.
语态其实在汉语中也一样存在,记得小学时候的被动句式和把字句式吗?那就是被动语态和主动语态.
主语从句、宾语从句、表语从句和同位语从句都是名词性从句,说得简单点,这些从句都相当于一个名词,可以当做名词来进行使用.但是所有的从句,不管是定语从句,状语从句还是名词性从句,他们的前面都会有一个连接词,如which, what, when, where,how等等,连接词后面紧跟的往往是一个主谓结构（俗称陈述句语序）.
语法题解题的主要技巧还是要把每个题目当做阅读理解来做,要体会说话人的表达意图,了解其感情色彩,这样才会选择恰当的表达方式.
内容太多,真要讲清楚恐怕至少也得万把字,只能如此了.

下列说法正确的是（A）
A 零的平方根和立方根是零
B 1的平方根与立方根都的关于它本身
若一个数的平方根是正负八,则这个数的立方根是（A）
A 四 B 正负四 C 二 D正负二
这个较为有难度听好了：
如果一个球的体积为原来的8倍,那么它的半径为原来的多少倍?如果一个球的体积变为原来的27倍,那么它的半径变为原来的多少倍?如果球的体积变为原来的1000倍呢?变为原来的N倍呢?
答：如果一个球的体积为原来的8倍,那么它的半径为原来的2倍,如果一个球的体积变为原来的27倍,那么它的半径变为原来的3倍,如果球的体积变为原来的1000倍呢,那么它的半径变为原来的10倍.

how to make friends
everyone needs friends,so how to make real friends is very important to everyone.a good friend can make you a better person,a bad friend can destroy you in many different ways.to have a friend you may like,first you should be a good friend to others.so what's a 5 star friend?in my opinion,a good friend is kink to others ,he should have smile on his face anytime,he should be considerative,to think about what others think,and he should care about others more than himself.when good friends quarrel,they should calm down to think carefully about their own mistakes.some friends may destroy you,they are not real friends,that is,a friend in need is a friend indeed.
thanks!

1)x+y+2x-4y+3=0,∴(x+1)+(y-2)=2 直线L不过原点,且在xy轴上截距相等,则L斜率为-1 设L:y=-x+t,即x+y-t=0 L与圆相切,则圆心(-1,2)到直线的距离为半径√2 ∴|-1+2-t|/√(1+1)=√2 ∴|t-1|=2,t-1=2或-2 ∴t=3或-1,即L:y=-x+3或y=-x-1 ②设P(x,y),则|PO|=x+y,P到C圆心距离平方为(x+1)+(y-2) ∴|PM|=(x+1)+(y-2)-(√2)=x+y+2x-4y+3=0 ∵|PO|=|PM|,即|PO|=|PM| ∴x+y=x+y+2x-4y+3 ∴2x-4y+3=0,即P轨迹为2x-4y+3=0 2)由题意 圆心在x+2y=0上,设圆心(-2t,t) ∴半径平方=(-2t-2)+(t-3)=5t+2t+13 圆方程为 (x+2t)+(y-t)=5t+2t+13 圆心到直线x-y+1=0距离为 |-2t-t+1|/√(1+1)=|3t-1|/√2 由垂径定理,弦长为2√[5t+2t+13-(|3t-1|/√2)]=2√2 ∴5t+2t+13-(3t-1)/2=2 ∴t+10t+21=(t+3)(t+7)=0 ∴t=-3或t=-7 圆为(x-6)+(y+3)=52,或(x-14)+(y+7)=244 3)条件不明确,圆和直线怎么样没说明

In (On) a Sunday morning,i met a foreigner in a shop.He wanted to buy something,but he couldn't understand Chinese.So he was very anxious.Looking this,I went(came) up to him and asked him that(what) he wanted to buy.He said he wanted to buy a camera.So i(I) asked the assistant the prices of all the camera(cameras) in the shop.then I told the foreigner the prices and he chose the camera he liked.As (加上一个a)result,he was very thankful to me for my kind help,but(and) he praised me for my good English.This(It) was the first time that i talked to a foreign friend in English and helped him.I was great encouraged.I made up my minds（mind） to learn English better.通常会有一处是正确的,没有错误

f'(x0)

确切的说应该是近似于电源电压.不过对初中物理而言,就是电源电压.
因为电压表的电阻远远大于灯的电阻,所以把几乎所有的电源电压都占用了,所以测定的值近似于电源电压.

75=3*5^2
AB只有质因数3,5,且都至少有2个因数5
B有10个约数
10=2*5
=(1+1)(1+4)
B=3*5^4=1875
B含有4个因数5,所以A最多只能有2个因数5
A有12个约数
12=2*6
=(1+1)*(1+5)
12=3*4
=(1+2)*(1+3)
所以A=3^3*5^2=675
A+B=1875+675=2550

当活塞在管口时,所需的外力是最大的,设这个状态下,封闭空气压强是P2,长度是L2＝L　.则对管子有　F拉＋G＋P2*S＝P0*S而在开始状态下,封闭空气压强是P1,空气柱长度是　L1＝H,对管子有　G＋P1*S＝P0*S由　P1*L1＝P2*L2...

1.香蕉球又称弧线球.会变弯是因为空气在一个表面水平流动时,气压将降低,比如你在下嘴唇上贴一个纸条,然后向前吹气,纸条就会向上抬起来,这正是因为上方因空气流动使气压降低,纸条受力使然.弧线球发球时给了其一个侧向力使其旋转,这样球在运动时垂直于运动方向的两个面上的空气的相对速度就不一样了,使得球受到一个力的作用发生旋转.
2.机翼上方空气运动的速度大于机翼下方,机身获得一个向上的力,就飞起来了.快速运动就是为了获得足够的力.逆风

孤单是被海洋环绕的孤岛,身处浩瀚却坚强刚毅

人们都说：”桂林山水甲天下.“我们乘着木船荡漾在漓江上,来观赏桂林的山水.我看见过波澜壮阔的大海,玩赏过水平如镜的西湖,却从没看见过漓江这样的水.漓江的水真静啊,静得让你感觉不到它在流动；漓江的水真清啊,清得...