2018年广州市华师附中番禺学校初三一模英语试卷(含答案)

2018年广州市华师附中番禺学校初三一模英语试卷(含答案)
2018年广州市华师附中番禺学校初三一模英语试卷(含答案)

广州市华师附中番禺学校初三一模英语试卷

一、语法选择

A girl complained to her father about her hard life. She didn’t know ____1____ she had to do and wanted to give up. She felt ____2____ of fighting and fighting. One problem had been finished but another came. Her father ____3____ was a cook took her into the kitchen. He poured water into the pan(锅)and boiled it. While the water ____4____, in the first pan he put carrots, in the second he put some eggs and in the last he put some coffee. He waited for them for ____5____ minutes without any words. The girl closed her mouth and waited ____6____. She didn't know why her father was doing that. After about 20 minutes, her father turned ____7____ the stove, took out the carrots and put them in a bowl. He took out the eggs and put them into another bowl. After that the coffee ____8____ into a cup. Turning back to ____9____ daughter, he asked, “What do you see?” “Carrots, eggs and coffee,” she answered.

Her father told her to close her eyes and let her ____10____ the carrots. She did and felt that the carrots were soft. After that he asked her to take eggs and break them. Then, she got boiled and hard eggs. At last, the father told her to smell the coffee. “What’s the meaning, Father?” He explained that each one had ____11____ same unlucky experience---the boiled water, ____12____ each had a different reaction(反应). The strong and hard carrots had become soft and weak after ____13____ in the boiling water?” The eggs became hard in the boiled water. The coffee was very special and it ____14____ change the water. “Who are you?” asked the father, “When calamity(厄运)____15____ at your door, what’s your reaction? Are you carrots, eggs or coffee?”

1.A. which B. that C. how D. what

2.A. tires B. tiring C. tired D. tiredly

3.A. who B. whom C. whose D. who’s

4.A. boiled B. was boiled C. is boiling D. was boiling

5.A. few B. a few C. little D. a little

6.A. patient B. more patient C. patiently D. more patiently

7.A. up B. down C. on D. off

8.A. pour B. poured C. had poured D. was poured

9.A. he B. his C. him D. himself

10.A. touch B. touched C. to touch D. touching

11.A. a B. an C. the D. /

12.A. and B. but C. so D. unless

13.A. stay B. stayed C. to stay D. staying

14.A. could B. can C. may D. had better

15.A. knock B. knocks C. knocked D. knocking

二、完形填空

Are you a man or a mouse? When people ask this question they want to know whether you think you are a brave person or a coward(懦夫). But you will never really know the answer to this question ____1____ you are tested in real life. Some people ____2____ they are brave but when they come face to face with real danger, they act like cowards. Others consider themselves as cowards, but when they meet danger, they act like ____3____.

Lenny had always thought of himself as a ____4____ person. He got worried before examinations. He worried about his job and his health. All he wanted in life was to be safe and healthy. Then, on January 15th, 2002, a plane crashed into the Potomac River in Washington. Lenny went to the river to see what was happening. He saw a woman in the ice-cold water. Lenny did not feel afraid. He kept very ____5____ and did a very adventurous thing. He jumped into Potomac, swam to the woman, and kept her head above the water. Seventy-eight people died that day. Thanks to Lenny, it was not ____6____.

When you are in a very dangerous situation and feel afraid, the body automatically (自动地)produces a chemical in the blood. This chemical is called adrenalin(肾上激素). With adrenalin in the blood system, you actually feel stronger and stronger and are ready to fight or ____7____. However, when you are absolutely terrified, the body can produce too much adrenalin. When this ____8____, the muscles become very hard and you find you can’t move at all. You are paralyzed(使无能为力)with fear. This is ____9____ when we are very frightened, we sometimes say we are “petrified”. This word comes from a Greek word “petros”, which means “stone”. We are ____10____ frightened that we become stonelike.

1.A. when B. until C. after D. once

2.A. realize B. find C. think D. agree

3.A. soldiers B. mice C. heroes D. cowards

4.A. useful B. brave C. nervous D. bored

5.A. nervous B. calm C. frightened D. excited

6.A. an accident B. a mistake C. seventy-eight D. seventy-nine

7.A. run out B. run over C. run down D. run away

8.A. gets B. goes C. happens D. disappears

9.A. where B. how C. because D. why

10.A. really B. very C. such D. so

三、阅读

第一节阅读理解

A

Twenty years ago, I drove a taxi for a living and sometimes I had to work at night. One late night, I got a telephone call from a neighborhood. When I arrived there at 2:30 a.m., the only building was dark except for a single light in the first floor window. So I walked up and knocked at the door.

“Just a minute,” answered a weak voice. After a long time, the door opened and a small woman stood in front of me. Next to her was a small suitcase.

Quickly I took her suitcase to the car and then returned to hold her. She took my arm and we walked slowly to the car. She kept thanking me for my kindness. “It’s nothing”, I told her, “I just try to treat my passengers the way I would want my mother treated.”

When we got in the car, she asked, “Can you drive me through downtown?”

“But it's not the shortest way,” I replied.

“I’m in no hurry.” she said slowly, “I’m on my way to a hospice(临终医院). I don’t have any family left. The doctor says I don't have very long time.”

I quietly turned off the meter. For the next two hours, we drove through the city and passed the building where she had once worked, the neighborhood where she and her husband had lived, and some other special places. As the sun was rising, we stopped in front of a low building where two nurses were waiting.

“How much should I pay?” she asked. “Nothing.” I replied.

“But you have to make a living.”

“Oh, there are other passengers.” Without thinking, I bent and gave her a hug. She held onto me tightly and said, “You gave an old woman a little moment of joy, thank you.”

Sometime people may not remember exactly what you did or said. However, they’ll always remember how you made them feel.

1.Why did the weak woman want to travel through downtown?

A. She enjoyed the night in the downtown

B. She’d like to run away from other people.

C. She planned to go to a very far and quiet place.

D. She wanted to remind herself of past memories.

2. What do you think of the driver in the passage?

A. He was funny and active.

B. He was young and smart.

C. He was kind and patient.

D. He was serious and strange.

3. What might the underlined word “meter” mean in Chinese?

A. 计费器

B. 收音机

C. 后备箱

D. 安全带

4. Which of the following is TRUE according to the passage?

A. The weak woman was going on vacation with a small suitcase.

B. The writer was touched by the weak woman and did good to her.

C. The weak woman gave the writer some money to thank him for his help.

D. The writer took the woman to the new building where she would live.

5. Which is the best title of the passage?

A. A Strange Woman.

B. A Special Taxi Trip.

C. A Kind Taxi Driver.

D. A Dark and Late Night.

B

Barbara McClintock was one of the most important scientists of the twentieth century. She made important discoveries about genes(基因)and chromosomes(染色体).

Barbara McClintock was born in 1902 in Hartford, Connecticut. Her family moved to the Brooklyn area of New York City in 1908. Barbara was an active child with interests in sports and music. She also developed an interest in science.

She studied science at Cornell University in Ithaca, New York. Barbara was among a small number of undergraduate students to receive training in genetics in 1921. Years later, she noted that few college students wanted to study genetics.

Barbara McClintock decided to study botany, the scientific study of plants, at Cornell University. She completed her undergraduate studies in 1923. McClintock decided to continue her education at Cornell. She completed a master’s degree in 1925. Two years later, she finished all her requirements for a doctorate degree.

McClintock stayed at Cornell after she completed her education. She taught students botany. The 1930s was not a good time to be a young scientist in the United States. The country was in the middle of the great economic Depression. Millions of Americans were unemployed. Male scientists were offered jobs. But female geneticists were not much in demand.

An old friend from Cornell, Marcus Rhoades, invited McClintock to spend the summer of 1941 working at the Cold Spring Harbor Laboratory. It is a research center on Long Island, near New York City. McClintock started a temporary(临时的)job with the genetics department. A short time later, she accepted a permanent(永久的)position in the laboratory. This gave her the freedom to continue her research without having to teach or repeatedly ask for financial aid.

By the 1970s, her discoveries had had an effect on everything from genetic engineering to cancer research. McClintock won the Nobel Prize for Physiology or Medicine in 1983 for her discovery of the ability of genes to change positions on chromosomes. She was the first American woman to win an unshared Nobel Prize.

1.When did McClintock get a doctorate degree?

A.In 1921

B. In 1923

C. In 1925

D. In 1927

2.During the great economic depression in the US, ________.

A. young scientists had trouble finding a job

B. female geneticists were not wanted at all

C. male geneticists were in great demand

D. male scientists were out of work

3. Which of the following jobs may be most beneficial to I McClintock’s research?

A. The job as a botany teacher.

B. The temporary job in the genetics department.

C. The permanent position in the laboratory.

D. The job of cancer research.

4. McClintock was awarded a Nobel Prize because of ________.

A. her research in botany

B. her contribution to genetic engineering

C. her discoveries about genes and chromosomes

D. her unshared work in the laboratory

5. The text is likely to appear in ________.

A. a biography

B. a history paper

C. a comic strip

D. a science fiction

C

Do you look like your name? Scientists say there’s a good chance you do.

This comes from a new study published in a magazine. Researchers from Israel found that our given names may have something to do with our facial appearances.

Lead writer Yonat Zwebner of a university, along with her team, did eight different experiments in Israel and France. The different experiments were set up to answer two main questions: whether people can correctly guess a person’s name based only on a photo of a face and what is behind this matching effect.

During the experiments, researchers asked students to look at photos of people’s faces and guess each person’s name from a list of four choices. They correctly guessed the right name 38 percent of the time, which was better than the 25 percent of a random(随机地)guess.

What’s more, when the faces the students looked at came from within their own country, they were able to best match the faces to the names. French students were better at matching only French names and faces while Israeli students were better at matching only Hebrew names and Israeli faces.

Researchers believe it is possible that people change their appearances without paying attention to it, to match their names. One study especially backed up this idea, showing that a hairstyle, something that can be changed by people easily, was enough to guide others in correctly guessing their names.

“Earlier research has shown there are cultural stereotypes(老套观念)carried by names, including how someone should look. For example, people are more likely to imagine a person named Bob to have a rounder face than a person named Tim. We believe these stereotypes can, over time, influence people’s facial appearances,” Zwebner said.

The results of the experiments may even make parents think twice when choosing a name for their children.

“If a name can influence appearance, it can influence many other things. This research opens an important direction that may suggest how parents should consider better the names for their children,” said Zwebner, who recently had a baby herself.

“As parents, it was really difficult for us to name our 12-day-old daughter as we know the meanings of names.”

1.One of the purposes of the experiments is to ________.

A.give the students a chance to know each other

B.explain what influences our facial appearances

C.find out different characteristics carried by different names

D.see if people can correctly guess a person’s name based only on a photo of a face

2.People could match the faces to the names more easily ________.

A.when they did a random guess

B.when the faces are from other countries

C.when the faces are from their own country

D.when they have more knowledge themselves

3.The underlined part "backed up' in Paragraph 6 most probably means “________”.

A.supported

B. changed

C. compared

D. cancelled

4.Paragraph 6 and Paragraph 7 are mainly to show ________.

A.the results of changing names

B. names have something to do with appearances

C. the importance of cultural stereotypes carried by names

D. the importance of a hairstyle in guessing different looks

5. According to Zwebner, we know that ________.

A. facial appearances may influence names

B. we shouldn't think of others just according to their names

C. a name may influence many things and should be well chosen

D. we should pay less attention to the meanings of names and be ourselves

D

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Every year thousands of old people are in need of our help. The Help Line provides a heartwarming, helpful, kind support and information service for the English-speaking aged people. We are in need of volunteers who are: *good listeners, warm-hearted and patient

*excellent English speaker

*can work 10 hours every week

Please call us at 0241-85902 or email us: helper@https://www.360docs.net/doc/4a2658036.html,.

(3)Save the Earth Club

Earth club is for any student in Green school, neighbor-hood, and city cleaner by encouraging recycling, highway clean up, and river, lake and school campus clean up. We hope to improve the environment and encourage others to do the same. We also meet to discuss some real solutions to saving the earth. Earth Club meets 2-4 times a month and join us!

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My great, great grandfather invented the carpet sweeper 125 years ago. This King Sweeper is by far the best. I invite you to try it in your home. You'll find it used daily in hospitals, restaurants, offices and homes throughout the world. This is just the thing to keep your carpet soft, clean and fresh. Only for $ 23.99!

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They can protect your eyes when driving, gardening or reading in the sun. It can make your life easier and happier, and make you look smarter! 10.99 each or 2 for 19.99.

1.If you are not getting on well with a friend of yours, you can email ________ for help.

A. Save The Earth Club

B. The King Sweeper

C. Help Line V olunteers

D. Dear Mrs. Web

2. Which of the following has the least chance to get help from Help Line Volunteers?

A. An old American farmer.

B. An old English farmer.

C. An old Chinese farmer.

D. An old Canadian farmer.

3. Save the Earth Club is ________ to help improve the environment.

A. a world club

B. a city club

C. a school club

D. a neighborhood club

4. If you buy a King Sweeper and two pairs of Trendy Sun-glass, you will save ________.

A. $ 10.9

B. $ 1.99

C. $ 19.99

D. $ 2.99

5. You probably read the information ________.

A. on a yard sale

B. on a talk show

C. in a science magazine

D. on the internet

第二节阅读填空

Face the Stress

Have you had a headache during a test? Have you ever been so worried about something that you have a headache or even can’t sleep at night? If so, then you know what stress is. Stress is what you feel when you are worried about something. ____1____ You may feel angry, sad, scared, or afraid --- all of which give you a stomachache or a headache.

____2____ Some kinds of stress are good and others are bad. Good stress might happen when you're called to answer questions in class or when you have to give a speech. ____3____ For example, you may do a better job in your test if the stress pushes you to prepare better before the test,

On the other hand, bad stress can happen if the stress lasts too long. You may not feel well if your parents are fighting, if a family member is sick, if you’re having problems at school, or if anything else makes you unhappy every day. That kind of stress isn't going to help you. ____4____

____5____ Make sure you keep yourself in mind: Sleep, exercise, leisure, and food. If you get enough sleep and eat healthily, and if you exercise and leave time for fun, you'll probably fell less stressed.

A.This is kind of stress can help you to get things better done.

B.This worry in your mind can make your body feel bad.

C.The best way to face the stress is to have a balanced life.

D.And it can actually make you sick.

E.However, there are different kinds of stress.

四、写作

第一节单词拼写

1. She felt n________ when talking in front of her class and her face turned red.

2. Where are you going for the summer v________.

3. There must be something wrong with this machine, because it’s almost d________.

4. If you don’t study hard, I am afraid you will f________ the exam again.

5. His sudden arrival made all the people look at him in s________.

6. He is so h________ with everybody that we all believe him.

第二节完成句子

1. 我习惯每天早起做运动。

I ________ ________ ________ ________ up early to do sports every day.

2.她想知道在哪可以买到这本书。

She wondered ________ ________ ________ ________ the book.

3.在这场大火中,大面积的森林被烧毁。

Huge areas of forests ________ ________ in this big fire.

4.多么激动人心的一场足球比赛啊!

________ ________ ________ football match it is!

5.似乎台风要来了。

________ ________ ________ a typhoon is coming.

6.这本书很有趣,我们都很喜欢阅读。

This is ________ ________ ________ ________ that we all enjoy reading it.

7.她的笑容和你一样甜。

Her smile is ________ ________ ________ ________.

第三节书面表达

目前,中学生早餐问题已经引起社会的广泛关注,你所在学校的学生会在3月20日"全国学生营养日" 开展了一次问卷调查。请根据调查结果写一篇英语短文,倡导学生们吃营养早餐。

注意:

1. 词数80左右(文章的开头已给出,不计入总词数);

2. 不得透露学校、姓名等任何个人信息,否则不予评分。

Breakfast Is Important

Breakfast is important. But not all the students have realized its importance. Here are the results of our survey.

_______________________________________________________________________________________________ ___

高三数学南方凤凰台高2021届高2018级高三一轮数学提高版完整版学案第八章

第八章 解析几何 第41讲 直线的斜率与方程 A 应知应会 一、 选择题 1. (2019·开封模拟)过点A (-1,-3),斜率是直线y =3x 的斜率的-1 4 的直线方程为 ( ) A. 3x +4y +15=0 B. 3x +4y +6=0 C. 3x +y +6=0 D. 3x -4y +10=0 2. 直线2x cos α-y -3=0??? ?α∈????π6,π3 的倾斜角的取值范围是 ( ) A. ????π6,π3 B. ????π4,π3 C. ????π4,π2 D. ????π4,2π 3 3. (2019·湖北四地七校联考)已知函数f (x )=a sin x -b cos x (a ≠0,b ≠0),若f ????π4-x =f ????π4+x ,则直线ax -by +c =0的倾斜角为( ) A. π4 B. π3 C. 2π3 D. 3π 4 4. 如果A ·C <0且B ·C <0,那么直线Ax +By +C =0不通过( ) A. 第一象限 B. 第二象限 C. 第三象限 D. 第四象限 5. (2019·张家口模拟)若直线mx +ny +3=0在y 轴上的截距为-3,且它的倾斜角是直线3 x -y =33 的倾斜角的2倍,则( ) A. m =-3 ,n =1 B. m =-3 ,n =-3 C. m =3 ,n =-3 D. m =3 ,n =1 二、 解答题 6. 求过点A (1,3),斜率是直线y =-4x 的斜率的1 3 的直线方程.

7. 求适合下列条件的直线方程. (1) 经过点P(3,2),且在两坐标轴上的截距相等; (2) 求过点(2,1)且在x轴上的截距与在y轴上的截距之和为6的直线方程. B巩固提升 一、填空题 1. 直线x+3y+1=0的倾斜角是________. 2. 过点P(2,3)且在两坐标轴上截距相等的直线方程为________. 3. 已知直线l:(a-2)x+(a+1)y+6=0,则直线l恒过定点________. 4. (2019·江苏姜堰中学)已知△ABC的三个顶点A(-5,0),B(3,-3),C(0,2),则BC边上中线所在的直线方程为________. 二、解答题 5. (2019·启东检测)已知直线l:(2+m)x+(1-2m)y+4-3m=0. (1) 求证:不论m为何实数,直线l过一定点M; (2) 过定点M作一条直线l1,使夹在两坐标轴之间的线段被M点平分,求直线l1的方程. 6. 如图,射线OA,OB分别与x轴正半轴成45°和30°角,过点P(1,0)作直线AB分别交 OA,OB于A,B两点,当AB的中点C恰好落在直线y=1 2x上时,求直线AB的方程. (第6题)

2015年广州市中考数学试卷及答案

2015年广东省广州市中考数学试卷 一、选择题(本大题共10小题,每小题3分,满分30分) 1.四个数-3.14,0,1,2中为负数的是( ) (A) -3.14 (B) 0 (C) 1 (D) 2 2.将图1所示的图案以圆心为中心,旋转180°后得到的图案是( ) 3.已知⊙O 的半径是5,直线l 是⊙O 的切线,则点O 到直线l 的距离是( ) (A) 2.5 (B) 3 (C) 5 (D) 10 4. 两名同学生进行了10次三级蛙跳测试,经计算,他们的平均成绩相同,若要比较这两名同学的成绩哪一位更稳定,通常还需要比较他们成绩的( ) (A) 众数 (B) 中位数 (C) 方差 (D) 以上都不对 5. 下列计算正确的是( ) (A) ab ?ab =2ab (B)(2a)4 =2a 4 (C) 3a -a =3(a≥0) (D) a ?b =ab (a≥0,b≥0) 6.如图2是一个几何体的三视图,则该几何体的展开图可以是 ( ) 7.已知a 、b 满足方程组???? ? a +5 b =123a -b =4 ,则 a + b =( ) (A) -4 (B) 4 (C) -2 (D) 2 8. 下列命题中,真命题的个数有( ) ①对角线互相平分的四边形是平行四边形, ②两组对角线分别相等的四边形是平行四边形. ③一组对边平行,另一组对边相等的四边形是平行四边形. (A) 3个 (B) 2个 (C) 1个 (D) 0个 9. 已知圆的半径是23,则该圆的内接正六边形的面积是( ) (A) 3 3 (B) 9 3 (C) 18 3 (D) 36 3 10.已知2是关于x 的方程x 2-2mx +3m =0的一个根,并且这个方程的两个根恰好是等腰三角形ABC 的两条边长,则三角形ABC 的周长为( ) (A) 10 (B) 14 (C) 10或14 (D) 8或10 二、填空题(6小题,每小题3分) 11.如图3,AB ∥CD ,直线l 分别与AB 、CD 相交,若∠1= 50°,则∠2的度数为 . 12.根据环保局公布的广州市2013年到2014年PM2.5 的主要来源的数据,制成扇形统计图(如图4).其中所占百分比最大的主要来源是 (填主要来源的名称) 13.分解因式:2mx -6my = . 14.某水库的水位在5小时内持续上涨,初始的水位高度为6米,水位以每小时0.3米的速度匀速上升,则水库的水位高度y 米与时间x 小时0≤x≤5的函数关系式 为 . 15.如图5,△ABC 中,DE 是BC 的垂直平分线,DE 交AC 于点E ,连接BE ,若BE =9,BC =12,则cosC = . 16.如图6,四边形ABCD 中,∠A =90°,AB =33,AD =3,点M 、N 分别线段BC 、AB 上的动点(含 端点,但点M 不与点B 重合),点E ,F 分别为DM 、MN 的中点 ,则EF 长度的最大值为 . 三、解答题(本大题共9小题,满分102分) 17.(9分)解方程:5x =3(x -4). (A) (B) (C) (D) 图1 (A ) (B ) (C ) (D ) 图2 主视图 左视图 俯视图 A B C D 图3 l 1 2 其它 19% 20.6% 11.5% 21.7% 10.4% 8.6% 8.2% 生物质 燃烧 扬尘 机动车 尾气 工业工 艺源 燃煤 生活 垃圾 图4 A B C D E A C D E F M N

广州近三年中考数学试题分析

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注:2011及2012年对比加粗部分为占比变化较大的板块。表2 2013广州中考数学试卷中各版块分值分布

注:灰色部分为多个知识点综合题. 二、试题分析 1.在内容上,2013年广州中考数学在各板块所占比重与上年基本持平,但函数部分占比下降明显,2012年填选题3题,解答题2题,2013年填空题1题,解答题2题。数与式部分题目量增加,所占分值较上年有所增加。本卷统计与概率结合同一解答题考查,统计概论板块所占分值下降。 2.2013年广州中考数学没有考查找规律,也没考查方程、不等式或函数的应用题,而增加了尺规作图的考查,还是要求考生掌握基本作图方法。 3.在难度上,与上年相比,2013年中考数学试题前22题难度相对较小,考察的题型也比较常规,基本上都是基础的知识,如有理数大小比较、数与式部分基础题型、全等三角形的判定和尺规作图、四边形的性质。结合的知识点较多,往往一个题目中涵盖多个考点。考查依旧重基础,要求常规题型熟练掌握。 4.考生普遍反应除两道压轴外,23题考查反比例函数与动点面积问题难度较大。24题尽管考查圆与相似三角形结合的问题,但是难度并不大,易错点在于分类讨论。25题二次函数问题并没有考查其与图形结合问题,而是较纯粹地考查二次函数的基本概念及性质,尽管难度不大,但会让部分考生不知所措。 5.在试题的选取上,延续了近几年出题的规律,后面两道压轴题一道几何(圆)一道二次函数,在上文讲到难度并不大,为了均衡试卷难度,23题就相应比前几年的考试难度大。 三、2014广州中考复习启示 1.以考纲为依据,重基础,认真复习常规题型。 尽管2013年广州中考数学试题23题较难,但是并不违背其多年的出题规律:前23题为基础考查,结合考点较少,难度一般不大。2014年中考复习先要紧抓考纲,巩固基础。 2. 掌握分类讨论、数形结合等数学思想; 2013广州中考数学试题24题考查了分类讨论,25题考查数形结合,这两个思想一直是中考考查热点。2014年中考复习要做到能够熟练运用数学思想,解决综合问题。 3.有针对性的练习提高学生解决综合问题的能力。 进行2014年广州中考数学复习的同学可在自己能够接受得范围内自觉进行综合题练习,既能够复习巩固基础考点,也能够练习分类讨论或数形结合的数学思想的运用。 Ps:函数部分是代数部分的重点内容,也是难点内容,考查重点在于以下几点:函数解析式的求法,难度较低,熟悉待定系数法等方法即可;三种函数图像的基本性质的应用,难度中等;函数的实际应用,常出现在试卷难度最大的代数综合题、代几综合题中,分值在25分左右。 不等式与方程的复习,要以基础为主,不要只研究难题,要注重过程以及方法的总结。从试卷这部分考题来看,难度都不大,关键是我们的同学能否有明确的思路,良好的解题过程,正确答案。因此我们在复习的时候,一定要特别注意。加强对以下内容的复习:一元一次方程、二元一次方程组、一元一次不等式、不等式组、一元二次方程。注意整体思想,换

2018年高考理科数学第一轮复习教案34 不等关系与不等式

第一节不等关系与不等式 不等式的概念和性质 了解现实世界和日常生活中的不等关系,了解不等式(组)的实际背景. 知识点一实数的大小顺序与运算性质的关系 (1)a>b?a-b>0; (2)a=b?a-b=0; (3)a

1.已知a1,a2∈(0,1),记M=a1a2,N=a1+a2-1,则M与N 的大小关系是() A.MN C.M=N D.不确定 解析:M-N=a1a2-(a1+a2-1)=a1a2-a1-a2+1=a1(a2-1)-(a2-1)=(a1-1)(a2-1), 又∵a1∈(0,1),a2∈(0,1),∴a1-1<0,a2-1<0. ∴(a1-1)(a2-1)>0,即M-N>0.∴M>N. 答案:B 知识点二不等式性质

易误提醒 1.在应用传递性时,注意等号是否传递下去,如a ≤b ,b b ?ac 2>bc 2;若无c ≠0这个条件,a >b ?ac 2>bc 2就是错误结论(当c =0时,取“=”). [自测练习] 2.设a ,b ,c ∈R ,且a >b ,则( ) A .ac >bc B.1a <1 b C .a 2>b 2 D .a 3>b 3 解析:当c <0时,ac >bc 不成立,故A 不正确,当a =1,b =-3时,B 、C 均不正确,故选D. 答案:D 3.若a >b >0,则下列不等式中恒成立的是( ) A.b a >b +1a +1 B .a +1a >b +1 b C .a +1b >b +1 a D.2a +b a +2b >a b

2018年广东省广州市中考数学试卷及解析

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的小球,分别写有数字1和2.从两个口袋中各随机取出1个小球,取出的两个小球上都写有数字2的概率是() A.B.C.D. 7.(3分)如图,AB是⊙O的弦,OC⊥AB,交⊙O于点C,连接OA,OB,BC,若∠ABC=20°,则∠AOB的度数是() A.40°B.50°C.70°D.80° 8.(3分)《九章算术》是我国古代数学的经典著作,书中有一个问题:“今有黄金九枚,白银一十一枚,称之重适等.交易其一,金轻十三两.问金、银一枚各重几何?”.意思是:甲袋中装有黄金9枚(每枚黄金重量相同),乙袋中装有白银11枚(每枚白银重量相同),称重两袋相等.两袋互相交换1枚后,甲袋比乙袋轻了13两(袋子重量忽略不计).问黄金、白银每枚各重多少两?设每枚黄金重x两,每枚白银重y两,根据题意得() A.B. C.D. 9.(3分)一次函数y=ax+b和反比例函数y=在同一直角坐标系中的大致图象是() A.B.

2018年高考数学一轮复习感知高考第116—120题(含答案解析)

高考一轮复习116 1.已知ABC ?中,角,,A B C 的对边,,a b c 满足()c o s c a A C =+,则tan C 的最大值是 . 解:()222 cos cos 2a c b c a A C a B a ac +-=+=-=-? 即() 22213c b a =-,且B 为钝角,C 为锐角 由余弦定理得( )2222222221423cos 226a b b a a b c a b C ab ab ab +--+-+===≥ 锐角C 在区间0,2π?? ??? 上递减,故当( )min cos C =,则( )max tan C =2.各大学在高考录取时采取专业志愿优先的录取原则.一考生从某大学所给的7个专业中,选择3个作为自己的第一、二、三专业志愿,其中甲、乙两个专业不能同时兼报,则该考生有______种不同的填报专业志愿的方法(用数字作答). 解:327 35180A A -?= 高考一轮复习117 1.已知,αβ为锐角,且()sin cos sin ααββ+= ,则tan α的最大值是 . 解法一:()()()()sin sin cos sin cos cos sin sin sin αββαββααβαββββ ?+-?+??+===-+ 即()tan 2tan αββ+= ()()( )2tan tan tan tan tan 1tan tan 12tan αβββααββαβββ+-=?+-?= ==??+++ 当且仅当tan β= 解法二:由()sin cos sin ααββ+=得sin cos cos sin sin sin ααβαββ -= 即1cos cos sin sin sin αβαββ??=+ ???

2013年广州市中考数学试卷及答案(解析版)

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