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新人教版高中英語必修3Unit 5 the value of money-Reading For Writing教學設(shè)計一
【參考范文】Narrator：(Henry is smiling as he leaves the restaurant. As he is walking down the street, he sees a sign for a place that cuts hair. He decides to get it cut. )H＝Henry；B＝Barber；R＝rude manH：Good afternoon, I'd like to get a cut, if I may. (The barber looks at Henry's hair and continues cutting another man's hair. )Er, I'd really like a haircut. As you can see it's much too long. B：(in a rude manner) Yes, I can see that. Indeed, I can. H：Fine, well I'll have a seat then. (He sits in one of the barber's chairs. The barber turns to look at Henry. )B：It's quite expensive here, you know！Are you sure you can afford it?H：Yes. I think so. (In comes the rude man. )R：Hey you there. I need a haircut quickly. Can you do me straightaway?B：All right, then, get in the chair and I'll see what I can do. R：Thank you. (sits down in one of the barber's chairs)H：Excuse me, but I was here first. Aren't you going to do my hair first?B：This man's in a hurry. H：Well so am I！I insist that you cut my hair first. B：OK, but I'll have to be quick. This gentleman is waiting. H：Thank you. (They both become quiet. After his hair is cut, the barber tells Henry how much he must pay. Henry shows the barber the bank note. )B：Why, Mr . . . (looks shocked)H：Adams. Henry Adams. I'm sorry, I don't have any change. R：You're that Mr Adams! Well，I'm glad I waited or I might never have known it was you. B：Why, Mr Adams, please don't worry！(wearing a big smile) Nothing to worry about！Nothing at all!Please come back any time, even if you only need too little hairs cut！It will be my honour to serve you!
新人教版高中英語選修2Unit 1 Science and Scientists-Discovering useful structures教學設(shè)計
The grammatical structure of this unit is predicative clause. Like object clause and subject clause, predicative clause is one of Nominal Clauses. The leading words of predicative clauses are that, what, how, what, where, as if, because, etc.The design of teaching activities aims to guide students to perceive the structural features of predicative clauses and think about their ideographic functions. Beyond that, students should be guided to use this grammar in the context apporpriately and flexibly.1. Enable the Ss to master the usage of the predicative clauses in this unit.2. Enable the Ss to use the predicative patterns flexibly.3. Train the Ss to apply some skills by doing the relevant exercises.1.Guide students to perceive the structural features of predicative clauses and think about their ideographic functions.2.Strengthen students' ability of using predicative clauses in context, but also cultivate their ability of text analysis and logical reasoning competence.Step1: Underline all the examples in the reading passage, where noun clauses are used as the predicative. Then state their meaning and functions.1) One theory was that bad air caused the disease.2) Another theory was that cholera was caused by an infection from germs in food or water.3) The truth was that the water from the Broad Street had been infected by waste.Sum up the rules of grammar:1. 以上黑體部分在句中作表語。2. 句1、2、3中的that在從句中不作成分，只起連接作用。 Step2: Review the basic components of predicative clauses1.Definition
新人教版高中英語選修2Unit 4 Journey Across a Vast Land教學設(shè)計
當孩子們由父母陪同時，他們才被允許進入這個運動場。3．過去分詞(短語)作狀語時的幾種特殊情況(1)過去分詞(短語)在句中作時間、條件、原因、讓步狀語時，相當于對應(yīng)的時間、條件、原因及讓步狀語從句。Seen from the top of the mountain (＝When it is seen from the top of the mountain), the whole town looks more beautiful.從山頂上看，整個城市看起來更美了。Given ten more minutes (＝If we are given ten more minutes), we will finish the work perfectly.如果多給十分鐘，我們會完美地完成這項工作。Greatly touched by his words (＝Because she was greatly touched by his words), she was full of tears.由于被他的話深深地感動，她滿眼淚花。Warned of the storm (＝Though they were warned of the storm), the farmers were still working on the farm.盡管被警告了風暴的到來，但農(nóng)民們?nèi)栽谵r(nóng)場干活。(2)過去分詞(短語)在句中作伴隨、方式等狀語時，可改為句子的并列謂語或改為并列分句。The teacher came into the room, followed by two students (＝and was followed by two students)．后面跟著兩個學生，老師走進了房間。He spent the whole afternoon, accompanied by his mom(＝and was accompanied by his mom)．他由母親陪著度過了一整個下午。
新人教版高中英語選修2Unit 1 Science and Scientists-Learning about Language教學設(shè)計
Step 7: complete the discourse according to the grammar rules.Cholera used to be one of the most 1.__________ (fear) diseases in the world. In the early 19th century, _2_________ an outbreak of cholera hit Europe, millions of people died. But neither its cause, 3__________ its cure was understood. A British doctor, John Snow, wanted to solve the problem and he knew that cholera would not be controlled _4_________ its cause was found. In general, there were two contradictory theories 5 __________ explained how cholera spread. The first suggested that bad air caused the disease. The second was that cholera was caused by an _6_________(infect) from germs in food or water. John Snow thought that the second theory was correct but he needed proof. So when another outbreak of cholera hit London in 1854, he began to investigate. Later, with all the evidence he _7_________ (gather), John Snow was able to announce that the pump water carried cholera germs. Therefore, he had the handle of the pump _8_________ (remove) so that it couldn't be used. Through his intervention，the disease was stopped in its tracks. What is more, John Snow found that some companies sold water from the River Thames that __9__________________ (pollute) by raw waste. The people who drank this water were much more likely _10_________ (get) cholera than those who drank pure or boiled water. Through John Snow's efforts, the _11_________ (threaten) of cholera around the world saw a substantial increase. Keys： 1.feared 2.when 3. nor 4.unless 5.that/which 6.infection 7.had gathered 8.removed 9.was polluted 10.to get 11. threat
新人教版高中英語選修2Unit 1 Science and Scientists-Reading and thinking教學設(shè)計
Step 5： After learning the text, discuss with your peers about the following questions:1.John Snow believed Idea 2 was right. How did he finally prove it?2. Do you think John Snow would have solved this problem without the map?3. Cholera is a 19th century disease. What disease do you think is similar to cholera today?SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.keys:1. John Snow finally proved his idea because he found an outbreak that was clearly related to cholera, collected information and was able to tie cases outside the area to the polluted water.2. No. The map helped John Snow organize his ideas. He was able to identify those households that had had many deaths and check their water-drinking habits. He identified those houses that had had no deaths and surveyed their drinking habits. The evidence clearly pointed to the polluted water being the cause.3. SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.Step 6: Consolidate what you have learned by filling in the blanks:John Snow was a well-known _1___ in London in the _2__ century. He wanted to find the _3_____ of cholera in order to help people ___4_____ it. In 1854 when a cholera __5__ London, he began to gather information. He ___6__ on a map ___7___ all the dead people had lived and he found that many people who had ___8____ (drink) the dirty water from the __9____ died. So he decided that the polluted water ___10____ cholera. He suggested that the ___11__ of all water supplies should be _12______ and new methods of dealing with ____13___ water be found. Finally, “King Cholera” was __14_____.Keys: 1. doctor 2. 19th 3.cause 4.infected with 5.hit 6.marked 7.where 8.drunk 9.pump 10.carried 11.source 12.examined 13.polluted 14.defeatedHomework: Retell the text after class and preview its language points
新人教版高中英語選修2Unit 1 Science and Scientists-Using langauge教學設(shè)計
This happens because the dish soap molecules have a strong negative charge, and the milk molecules have a strong positive charge. Like magnets, these molecules are attracted to each other, and so they appear to move around on the plate, taking the food coloring with them, making it look like the colors are quickly moving to escape from the soap.Listening text:? Judy: Oh, I'm so sorry that you were ill and couldn't come with us on our field trip. How are you feeling now? Better?? Bill: Much better, thanks. But how was it?? Judy: Wonderful! I especially liked an area of the museum called Light Games.it was really cool. They had a hall of mirrors where I could see myself reflected thousands of times!? Bill: A hall of mirrors can be a lot of fun. What else did they have?? Judy: Well, they had an experiment where we looked at a blue screen for a while, and then suddenly we could see tiny bright lights moving around on it. You'll never guess what those bright lights were!? Bill: Come on, tell me!? Judy: They were our own blood cells. For some reason, our eyes play tricks on us when we look at a blue screen, and we can see our own blood cells moving around like little lights! But there was another thing I liked better. I stood in front of a white light, and it cast different shadows of me in every color of the rainbow!? Bill: Oh, I wish I had been there. Tell me more!? Judy: Well, they had another area for sound. They had a giant piano keyboard that you could use your feet to play. But then, instead of playing the sounds of a piano, it played the voices of classical singers! Then they had a giant dish, and when you spoke into it, it reflected the sound back and made it louder. You could use it to speak in a whisper to someone 17 meters away.? Bill: It all sounds so cool. I wish I could have gone with you? Judy: I know, but we can go together this weekend. I'd love to go there again!? Bill: That sounds like a great idea!
新人教版高中英語選修2Unit 2 Bridging Cultures-Discovering useful structures教學設(shè)計
The grammar of this unit is designed to review noun clauses. Sentences that use nouns in a sentence are called noun clauses. Nominal clauses can act as subject, object, predicate, appositive and other components in compound sentences. According to the above-mentioned different grammatical functions, nominal clauses are divided into subject clause, object clause, predicate clause and appositive clause. In this unit, we will review the three kinds of nominal clauses. Appositive clauses are not required to be mastered in the optional compulsory stage, so they are not involved.1. Guide the students to judge the compound sentences and determine the composition of the clauses in the sentence.2. Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.3. Inspire the students to systematize the function and usage of noun clause1.Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.2.Inspire the students to systematize the function and usage of noun clauseStep1: The teacher ask studetns to find out more nominal clauses from the reading passage and udnerline the nominal clauses.
新人教版高中英語選修2Unit 3 Food and Culture-Discovering useful structures教學設(shè)計
The newspaper reported more than 100 people had been killed in the thunderstorm.報紙報道說有一百多人在暴風雨中喪生。(2)before、when、by the time、until、after、once等引導的時間狀語從句的謂語是一般過去時，以及by、before后面接過去的時間時，主句動作發(fā)生在從句的動作或過去的時間之前且表示被動時，要用過去完成時的被動語態(tài)。By the time my brother was 10, he had been sent to Italy.我弟弟10歲前就已經(jīng)被送到意大利了。Tons of rice had been produced by the end of last month. 到上月底已生產(chǎn)了好幾噸大米。(3) It was the first/second/last ... time that ...句中that引導的定語從句中，主語與謂語構(gòu)成被動關(guān)系時，要用過去完成時的被動語態(tài)。It was the first time that I had seen the night fact to face in one and a half years. 這是我一年半以來第一次親眼目睹夜晚的景色。(4)在虛擬語氣中，條件句表示與過去事實相反，且主語與謂語構(gòu)成被動關(guān)系時，要用過去完成時的被動語態(tài)。If I had been instructed by him earlier, I would have finished the task.如果我早一點得到他的指示，我早就完成這項任務(wù)了。If I had hurried, I wouldn't have missed the train.如果我快點的話，我就不會誤了火車。If you had been at the party, you would have met him. 如果你去了晚會，你就會見到他的。
新人教版高中英語選修2Unit 3 Food and Culture-Reading and thinking教學設(shè)計
The discourse explores the link between food and culture from a foreign’s perspective and it records some authentic Chinese food and illustrates the cultural meaning, gerography features and historic tradition that the food reflects. It is aimed to lead students to understand and think about the connection between food and culture. While teaching, the teacher should instruct students to find out the writing order and the writer’s experieces and feelings towards Chinese food and culture.1.Guide the students to read the text, sort out the information and dig out the topic.2.Understand the cultural connotation, regional characteristics and historical tradition of Chinese cuisine3.Understand and explore the relationship between food and people's personality4.Guide the students to use the cohesive words in the text5.Lead students to accurately grasp the real meaning of the information and improve the overall understanding ability by understanding the implied meaning behind the text.1. Enable the Ss to understand the structure and the writing style of the passage well.2. Lead the Ss to understand and think further about the connection between food and geography and local character traits.Step1: Prediction before reading. Before you read, look at the title, and the picture. What do you think this article is about?keys:It is about various culture and cuisine about a place or some countries.
新人教版高中英語選修2Unit 5 First Aid-Discovering useful structures教學設(shè)計
You have no excuse for not going.你沒有理由不去。He was punished for not having finished his homework.他因未完成作業(yè)而受到懲罰。2．動詞ing形式復(fù)合結(jié)構(gòu)由物主代詞或人稱代詞賓格、名詞所有格或普通格加動詞ing，即“sb./sb.'s＋doing”構(gòu)成。動詞ing形式的復(fù)合結(jié)構(gòu)實際上是給動詞ing形式加了一個邏輯主語。動詞ing形式的復(fù)合結(jié)構(gòu)有四種形式：①形容詞性物主代詞＋動詞ing②名詞所有格＋動詞ing③代詞賓格＋動詞ing④名詞＋動詞ingHer coming to help encouraged all of us.她來幫忙鼓舞了我們所有人。The baby was made awake by the door suddenly shutting.這個嬰兒被突然的關(guān)門聲吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做飯的樣子嗎？無生命名詞無論是作主語還是作賓語都不能用第②種形式。Tom's winning first prize last year impressed me a lot.湯姆去年得了一等獎使我印象深刻。Do you mind my/me/Jack's/Jack leaving now?你介意我/杰克現(xiàn)在離開嗎？Excuse me for my not coming on time．很抱歉我沒能按時來。His father's being ill made him worried.他父親病了，他很擔心。We are looking forward to the singer's/the singer to give us a concert.我們盼望著這位歌手來給我們舉辦一場演唱會。
人教版高中地理選修3第五章第一節(jié)設(shè)計旅游活動教案
點撥：旅游地旅游資源的特色不同，可以安排的旅游活動是不一樣的，直接影響對旅游者的吸引力。因此，出游前首先就需要收集旅游地旅游資源的類型、主要游覽景區(qū)、景點的特色等情況。旅游地的時空可達性直接關(guān)系到旅游者從出發(fā)地到旅游地，然后再返回出發(fā)地的費用和時間。一般來說，居住地與旅游地之間的空間距離過大，會使旅行的時間過長、旅行費用過高，經(jīng)濟距離增加，相應(yīng)地降低了旅游者的出游能力。而居住地與旅游地相距遙遠，也意味著兩地之間巨大的環(huán)境差異，這會增加對游客的吸引力。旅游服務(wù)設(shè)施和條件，如旅游交通方式及工具、旅游住宿條件、旅游餐飲的種類和標準、導游服務(wù)、旅行費用等信息也都在一定程度上影響著游客的選擇。圖5．3西藏布達拉宮和圖5．4云南香格里拉兩幅圖片顯示了西藏布達拉宮、云南香格里拉與眾不同的優(yōu)美景觀，吸引了眾多的游客前來觀光旅游，成為近年來國內(nèi)旅游的熱點。
人教版新課標高中物理必修1用打點計時器測速度教案3篇
實驗?zāi)繕耍?、知道打點計時器的構(gòu)造和原理，學會使用打點計時器，能根據(jù)打出的紙帶計算打幾個點所用的時間，會計算紙帶的平均速度，能根據(jù)紙帶粗略測量紙帶的瞬時速度，認識v-t圖象，并能根據(jù)v-t圖象判斷物體的運動情況。2、通過速度測量過程的體驗，領(lǐng)悟兩個方法：一是用圖象處理物理數(shù)據(jù)的方法；二是極限法或說無限趨近法，加強一個認識，實驗是檢驗理論的標準。實驗器材：電源（220v電源或?qū)W生電源），打點計時器，紙帶，刻度尺（最好是塑料透明的），導線實驗準備：1、仔細觀察電磁打點計時器和電火花計時器，對照課本，比較它們的異同。2、兩類打點計時器的打點時間間隔是多少？3、分析紙帶時，如何計算紙帶的平均速度。4、嚴格地說，瞬時速度我們引進測量出來的，你知道用什么方法求出的速度可以代替某點的瞬時速度嗎？
人教版新課標高中物理必修1用打點計時器測速度教案3篇
實驗?zāi)繕耍?、知道打點計時器的構(gòu)造和原理，學會使用打點計時器，能根據(jù)打出的紙帶計算打幾個點所用的時間，會計算紙帶的平均速度，能根據(jù)紙帶粗略測量紙帶的瞬時速度，認識v-t圖象，并能根據(jù)v-t圖象判斷物體的運動情況。2、通過速度測量過程的體驗，領(lǐng)悟兩個方法：一是用圖象處理物理數(shù)據(jù)的方法；二是極限法或說無限趨近法，加強一個認識，實驗是檢驗理論的標準。實驗器材：電源（220v電源或?qū)W生電源），打點計時器，紙帶，刻度尺（最好是塑料透明的），導線實驗準備：1、仔細觀察電磁打點計時器和電火花計時器，對照課本，比較它們的異同。2、兩類打點計時器的打點時間間隔是多少？3、分析紙帶時，如何計算紙帶的平均速度。4、嚴格地說，瞬時速度我們引進測量出來的，你知道用什么方法求出的速度可以代替某點的瞬時速度嗎？5、從器材上讀取的數(shù)據(jù)是原始數(shù)據(jù)，原始數(shù)據(jù)是寶貴的實驗資料，要嚴肅對待，要整齊的記錄，妥善保存。
空間向量基本定理教學設(shè)計人教A版高中數(shù)學選擇性必修第一冊
反思感悟用基底表示空間向量的解題策略1.空間中,任一向量都可以用一個基底表示,且只要基底確定,則表示形式是唯一的.2.用基底表示空間向量時,一般要結(jié)合圖形,運用向量加法、減法的平行四邊形法則、三角形法則,以及數(shù)乘向量的運算法則,逐步向基向量過渡,直至全部用基向量表示.3.在空間幾何體中選擇基底時,通常選取公共起點最集中的向量或關(guān)系最明確的向量作為基底,例如,在正方體、長方體、平行六面體、四面體中,一般選用從同一頂點出發(fā)的三條棱所對應(yīng)的向量作為基底.例2.在棱長為2的正方體ABCD-A1B1C1D1中,E,F分別是DD1,BD的中點,點G在棱CD上,且CG=1/3 CD(1)證明:EF⊥B1C;(2)求EF與C1G所成角的余弦值.思路分析選擇一個空間基底,將(EF) ?,(B_1 C) ?,(C_1 G) ?用基向量表示.(1)證明(EF) ?·(B_1 C) ?=0即可;(2)求(EF) ?與(C_1 G) ?夾角的余弦值即可.(1)證明:設(shè)(DA) ?=i,(DC) ?=j,(DD_1 ) ?=k,則{i,j,k}構(gòu)成空間的一個正交基底.
點到直線的距離公式教學設(shè)計人教A版高中數(shù)學選擇性必修第一冊
4.已知△ABC三個頂點坐標A(－1,3)，B(－3,0)，C(1,2)，求△ABC的面積S.【解析】由直線方程的兩點式得直線BC的方程為 ＝ ，即x－2y＋3＝0，由兩點間距離公式得|BC|＝ ，點A到BC的距離為d，即為BC邊上的高，d＝ ，所以S＝ |BC|·d＝ ×2 × ＝4，即△ABC的面積為4.5.已知直線l經(jīng)過點P(0,2),且A(1,1),B(-3,1)兩點到直線l的距離相等,求直線l的方程.解:(方法一)∵點A(1,1)與B(-3,1)到y(tǒng)軸的距離不相等,∴直線l的斜率存在,設(shè)為k.又直線l在y軸上的截距為2,則直線l的方程為y=kx+2,即kx-y+2=0.由點A(1,1)與B(-3,1)到直線l的距離相等,∴直線l的方程是y=2或x-y+2=0.得("|" k"-" 1+2"|" )/√(k^2+1)=("|-" 3k"-" 1+2"|" )/√(k^2+1),解得k=0或k=1.(方法二)當直線l過線段AB的中點時,A,B兩點到直線l的距離相等.∵AB的中點是(-1,1),又直線l過點P(0,2),∴直線l的方程是x-y+2=0.當直線l∥AB時,A,B兩點到直線l的距離相等.∵直線AB的斜率為0,∴直線l的斜率為0,∴直線l的方程為y=2.綜上所述,滿足條件的直線l的方程是x-y+2=0或y=2.
兩點間的距離公式教學設(shè)計人教A版高中數(shù)學選擇性必修第一冊
一、情境導學在一條筆直的公路同側(cè)有兩個大型小區(qū),現(xiàn)在計劃在公路上某處建一個公交站點C,以方便居住在兩個小區(qū)住戶的出行.如何選址能使站點到兩個小區(qū)的距離之和最小?二、探究新知問題1.在數(shù)軸上已知兩點A、B，如何求A、B兩點間的距離？提示：|AB|＝|xA－xB|.問題2：在平面直角坐標系中能否利用數(shù)軸上兩點間的距離求出任意兩點間距離？探究.當x1≠x2，y1≠y2時，|P1P2|＝？請簡單說明理由．提示：可以，構(gòu)造直角三角形利用勾股定理求解．答案：如圖，在Rt △P1QP2中，|P1P2|2＝|P1Q|2＋|QP2|2，所以|P1P2|＝?x2－x1?2＋?y2－y1?2.即兩點P1(x1，y1)，P2(x2，y2)間的距離|P1P2|＝?x2－x1?2＋?y2－y1?2.你還能用其它方法證明這個公式嗎？2．兩點間距離公式的理解(1)此公式與兩點的先后順序無關(guān)，也就是說公式也可寫成|P1P2|＝?x2－x1?2＋?y2－y1?2.(2)當直線P1P2平行于x軸時，|P1P2|＝|x2－x1|.當直線P1P2平行于y軸時，|P1P2|＝|y2－y1|.
傾斜角與斜率教學設(shè)計人教A版高中數(shù)學選擇性必修第一冊
(2)l的傾斜角為90°,即l平行于y軸,所以m+1=2m,得m=1.延伸探究1 本例條件不變,試求直線l的傾斜角為銳角時實數(shù)m的取值范圍.解:由題意知(m"-" 1"-" 1)/(m+1"-" 2m)>0,解得1<m<2.延伸探究2 若將本例中的“N(2m,1)”改為“N(3m,2m)”,其他條件不變,結(jié)果如何?解:(1)由題意知(m"-" 1"-" 2m)/(m+1"-" 3m)=1,解得m=2.(2)由題意知m+1=3m,解得m=1/2.直線斜率的計算方法(1)判斷兩點的橫坐標是否相等,若相等,則直線的斜率不存在.(2)若兩點的橫坐標不相等,則可以用斜率公式k=(y_2 "-" y_1)/(x_2 "-" x_1 )(其中x1≠x2)進行計算.金題典例 光線從點A(2,1)射到y(tǒng)軸上的點Q,經(jīng)y軸反射后過點B(4,3),試求點Q的坐標及入射光線的斜率.解:(方法1)設(shè)Q(0,y),則由題意得kQA=-kQB.∵kQA=(1"-" y)/2,kQB=(3"-" y)/4,∴(1"-" y)/2=-(3"-" y)/4.解得y=5/3,即點Q的坐標為 0,5/3 ,∴k入=kQA=(1"-" y)/2=-1/3.(方法2)設(shè)Q(0,y),如圖,點B(4,3)關(guān)于y軸的對稱點為B'(-4,3), kAB'=(1"-" 3)/(2+4)=-1/3,由題意得,A、Q、B'三點共線.從而入射光線的斜率為kAQ=kAB'=-1/3.所以,有(1"-" y)/2=(1"-" 3)/(2+4),解得y=5/3,點Q的坐標為(0,5/3).
兩條平行線間的距離教學設(shè)計人教A版高中數(shù)學選擇性必修第一冊
一、情境導學前面我們已經(jīng)得到了兩點間的距離公式，點到直線的距離公式，關(guān)于平面上的距離問題，兩條直線間的距離也是值得研究的。思考1：立定跳遠測量的什么距離？A.兩平行線的距離 B.點到直線的距離 C. 點到點的距離二、探究新知思考2：已知兩條平行直線l_1,l_2的方程，如何求l_1 〖與l〗_2間的距離？根據(jù)兩條平行直線間距離的含義，在直線l_1上取任一點P（x_0,y_0 ），,點P（x_0,y_0 ）到直線l_2的距離就是直線l_1與直線l_2間的距離，這樣求兩條平行線間的距離就轉(zhuǎn)化為求點到直線的距離。兩條平行直線間的距離1. 定義：夾在兩平行線間的__________的長.公垂線段2. 圖示： 3. 求法：轉(zhuǎn)化為點到直線的距離.1．原點到直線x＋2y－5＝0的距離是( )A．2 B．3 C．2 D．5D [d＝|－5|12＋22＝5.選D.]
兩直線的交點坐標教學設(shè)計人教A版高中數(shù)學選擇性必修第一冊
1.直線2x+y+8=0和直線x+y-1=0的交點坐標是( )A.(-9,-10) B.(-9,10) C.(9,10) D.(9,-10)解析:解方程組{■(2x+y+8=0"," @x+y"-" 1=0"," )┤得{■(x="-" 9"," @y=10"," )┤即交點坐標是(-9,10).答案:B 2.直線2x+3y-k=0和直線x-ky+12=0的交點在x軸上,則k的值為( )A.-24 B.24 C.6 D.± 6解析:∵直線2x+3y-k=0和直線x-ky+12=0的交點在x軸上,可設(shè)交點坐標為(a,0),∴{■(2a"-" k=0"," @a+12=0"," )┤解得{■(a="-" 12"," @k="-" 24"," )┤故選A.答案:A 3.已知直線l1:ax+y-6=0與l2:x+(a-2)y+a-1=0相交于點P,若l1⊥l2,則點P的坐標為 . 解析:∵直線l1:ax+y-6=0與l2:x+(a-2)y+a-1=0相交于點P,且l1⊥l2,∴a×1+1×(a-2)=0,解得a=1,聯(lián)立方程{■(x+y"-" 6=0"," @x"-" y=0"," )┤易得x=3,y=3,∴點P的坐標為(3,3).答案:(3,3) 4.求證:不論m為何值,直線(m-1)x+(2m-1)y=m-5都通過一定點. 證明:將原方程按m的降冪排列,整理得(x+2y-1)m-(x+y-5)=0,此式對于m的任意實數(shù)值都成立,根據(jù)恒等式的要求,m的一次項系數(shù)與常數(shù)項均等于零,故有{■(x+2y"-" 1=0"," @x+y"-" 5=0"," )┤解得{■(x=9"," @y="-" 4"." )┤
人教版高中數(shù)學選擇性必修二等比數(shù)列的概念 (1) 教學設(shè)計
新知探究我們知道，等差數(shù)列的特征是“從第2項起，每一項與它的前一項的差都等于同一個常數(shù)” 。類比等差數(shù)列的研究思路和方法，從運算的角度出發(fā)，你覺得還有怎樣的數(shù)列是值得研究的？1.兩河流域發(fā)掘的古巴比倫時期的泥版上記錄了下面的數(shù)列:9,9^2,9^3,…,9^10; ①100,100^2,100^3,…,100^10; ②5,5^2,5^3,…,5^10. ③2.《莊子·天下》中提到：“一尺之錘，日取其半，萬世不竭.”如果把“一尺之錘”的長度看成單位“1”，那么從第1天開始，每天得到的“錘”的長度依次是1/2,1/4,1/8,1/16,1/32,… ④3.在營養(yǎng)和生存空間沒有限制的情況下，某種細菌每20 min 就通過分裂繁殖一代，那么一個這種細菌從第1次分裂開始，各次分裂產(chǎn)生的后代個數(shù)依次是2,4,8,16,32,64,… ⑤4.某人存入銀行a元，存期為5年，年利率為 r ，那么按照復(fù)利，他5年內(nèi)每年末得到的本利和分別是a(1+r),a〖(1+r)〗^2,a〖(1+r)〗^3,a〖(1+r)〗^4,a〖(1+r)〗^5 ⑥