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部編版語(yǔ)文八年級(jí)下冊(cè)《我一生中的重要抉擇》教案
（1）一個(gè)快落山的太陽(yáng)，跟大家講的，更多的是自己一生奮斗過(guò)來(lái)的體會(huì)。指61歲的老人。（2）加入人家說(shuō)我是權(quán)威，也許還馬馬虎虎。作者自謙的說(shuō)法，指成績(jī)還過(guò)得去。（3）明明是一個(gè)過(guò)去時(shí)態(tài)，大家誤認(rèn)為是現(xiàn)在時(shí)態(tài)。指作者認(rèn)為自己不適合再做權(quán)威了。（4）扶植年輕人我覺(jué)得是一種歷史的潮流，當(dāng)然我們要?jiǎng)?chuàng)造條件，就是把他們推到需要刺激的風(fēng)口浪尖上。比喻重要的崗位或市場(chǎng)的前沿?！靖形蚓示渥印?.所以我知道自己是一個(gè)下午四五點(diǎn)鐘的太陽(yáng)。各位呢，上午八九點(diǎn)鐘的太陽(yáng)，這是本科生；碩士生呢，九十點(diǎn)鐘的太陽(yáng)；博士生呢，十點(diǎn)十一點(diǎn)鐘的太陽(yáng)。比喻，拉近了與聽(tīng)眾的距離，倍感親切、期望和鼓舞。2.所以1992年前電視臺(tái)采訪我，我基本上都拒絕了。透過(guò)細(xì)節(jié)，體現(xiàn)了堅(jiān)持不懈的科研精神。
人教版高中政治選修3亞太經(jīng)濟(jì)合作組織：區(qū)域經(jīng)濟(jì)合作的新形式教案
（一）、亞太經(jīng)濟(jì)合作組織的宗旨和作用1、亞太經(jīng)合組織簡(jiǎn)介：（1）、地位——當(dāng)今世界最大的區(qū)域性經(jīng)濟(jì)合作組織（2）、性質(zhì)——是促進(jìn)亞太國(guó)家和地區(qū)經(jīng)濟(jì)合作、推動(dòng)共同發(fā)展的主要機(jī)構(gòu)。亞太經(jīng)濟(jì)合作組織(APEC，簡(jiǎn)稱亞太經(jīng)合組織)，是當(dāng)今世界最大的區(qū)域性經(jīng)濟(jì)合作組織，是促進(jìn)亞太國(guó)家和地區(qū)經(jīng)濟(jì)合作、推動(dòng)共同發(fā)展的主要機(jī)構(gòu)。相關(guān)鏈接：1989年11月，在澳大利亞的倡議下，澳大利亞、美國(guó)、加拿大、日本、韓國(guó)、新西蘭和東盟六國(guó)的外交與經(jīng)濟(jì)部長(zhǎng)在澳大利亞首都堪培拉召開(kāi)部長(zhǎng)級(jí)會(huì)議，正式宣告亞太經(jīng)合組織成立。此后，該組織不斷擴(kuò)大，到2004年底共有21個(gè)成員，既有美國(guó)、日本等發(fā)達(dá)國(guó)家，也有中國(guó)、馬來(lái)西亞、墨西哥等發(fā)展中國(guó)家。亞太經(jīng)合組織的宗旨是：為本地區(qū)人民的共同利益而保持經(jīng)濟(jì)的增長(zhǎng)與發(fā)展，促進(jìn)成員間經(jīng)濟(jì)的相互依存，加強(qiáng)開(kāi)放的多邊貿(mào)易體制，減少區(qū)域貿(mào)易和投資壁壘。
人教版高中數(shù)學(xué)選修3二項(xiàng)式定理教學(xué)設(shè)計(jì)
二項(xiàng)式定理形式上的特點(diǎn)(1)二項(xiàng)展開(kāi)式有n+1項(xiàng),而不是n項(xiàng).(2)二項(xiàng)式系數(shù)都是C_n^k(k=0,1,2,…,n),它與二項(xiàng)展開(kāi)式中某一項(xiàng)的系數(shù)不一定相等.(3)二項(xiàng)展開(kāi)式中的二項(xiàng)式系數(shù)的和等于2n,即C_n^0+C_n^1+C_n^2+…+C_n^n=2n.(4)在排列方式上,按照字母a的降冪排列,從第一項(xiàng)起,次數(shù)由n次逐項(xiàng)減少1次直到0次,同時(shí)字母b按升冪排列,次數(shù)由0次逐項(xiàng)增加1次直到n次.1．判斷(正確的打“√”，錯(cuò)誤的打“×”)(1)(a＋b)n展開(kāi)式中共有n項(xiàng)． ( )(2)在公式中，交換a，b的順序?qū)Ω黜?xiàng)沒(méi)有影響． ( )(3)Cknan－kbk是(a＋b)n展開(kāi)式中的第k項(xiàng)． ( )(4)(a－b)n與(a＋b)n的二項(xiàng)式展開(kāi)式的二項(xiàng)式系數(shù)相同． ( )[解析] (1)× 因?yàn)?a＋b)n展開(kāi)式中共有n＋1項(xiàng)．(2)× 因?yàn)槎?xiàng)式的第k＋1項(xiàng)Cknan－kbk和(b＋a)n的展開(kāi)式的第k＋1項(xiàng)Cknbn－kak是不同的，其中的a，b是不能隨便交換的．(3)× 因?yàn)镃knan－kbk是(a＋b)n展開(kāi)式中的第k＋1項(xiàng)．(4)√ 因?yàn)?a－b)n與(a＋b)n的二項(xiàng)式展開(kāi)式的二項(xiàng)式系數(shù)都是Crn.[答案] (1)× (2)× (3)× (4)√
人教版高中數(shù)學(xué)選修3成對(duì)數(shù)據(jù)的相關(guān)關(guān)系教學(xué)設(shè)計(jì)
由樣本相關(guān)系數(shù)??≈0.97,可以推斷脂肪含量和年齡這兩個(gè)變量正線性相關(guān)，且相關(guān)程度很強(qiáng)。脂肪含量與年齡變化趨勢(shì)相同.歸納總結(jié)1．線性相關(guān)系數(shù)是從數(shù)值上來(lái)判斷變量間的線性相關(guān)程度，是定量的方法．與散點(diǎn)圖相比較，線性相關(guān)系數(shù)要精細(xì)得多，需要注意的是線性相關(guān)系數(shù)r的絕對(duì)值小，只是說(shuō)明線性相關(guān)程度低，但不一定不相關(guān)，可能是非線性相關(guān)．2．利用相關(guān)系數(shù)r來(lái)檢驗(yàn)線性相關(guān)顯著性水平時(shí)，通常與0.75作比較，若|r|>0.75，則線性相關(guān)較為顯著，否則不顯著．例2. 有人收集了某城市居民年收入(所有居民在一年內(nèi)收入的總和)與A商品銷(xiāo)售額的10年數(shù)據(jù),如表所示.畫(huà)出散點(diǎn)圖，判斷成對(duì)樣本數(shù)據(jù)是否線性相關(guān)，并通過(guò)樣本相關(guān)系數(shù)推斷居民年收入與A商品銷(xiāo)售額的相關(guān)程度和變化趨勢(shì)的異同.
人教版高中數(shù)學(xué)選修3二項(xiàng)式系數(shù)的性質(zhì)教學(xué)設(shè)計(jì)
1.對(duì)稱性與首末兩端“等距離”的兩個(gè)二項(xiàng)式系數(shù)相等,即C_n^m=C_n^(n"-" m).2.增減性與最大值 當(dāng)k(n+1)/2時(shí),C_n^k隨k的增加而減小.當(dāng)n是偶數(shù)時(shí),中間的一項(xiàng)C_n^(n/2)取得最大值;當(dāng)n是奇數(shù)時(shí),中間的兩項(xiàng)C_n^((n"-" 1)/2) 與C_n^((n+1)/2)相等,且同時(shí)取得最大值.探究2.已知(1+x)^n =C_n^0+C_n^1 x+...〖+C〗_n^k x^k+...+C_n^n x^n 3.各二項(xiàng)式系數(shù)的和C_n^0+C_n^1+C_n^2+…+C_n^n=2n.令x=1 得(1+1)^n=C_n^0+C_n^1 +...+C_n^n=2^n所以，(a+b)^n 的展開(kāi)式的各二項(xiàng)式系數(shù)之和為2^n1. 在(a+b)8的展開(kāi)式中,二項(xiàng)式系數(shù)最大的項(xiàng)為 ,在(a+b)9的展開(kāi)式中,二項(xiàng)式系數(shù)最大的項(xiàng)為 . 解析:因?yàn)?a+b)8的展開(kāi)式中有9項(xiàng),所以中間一項(xiàng)的二項(xiàng)式系數(shù)最大,該項(xiàng)為C_8^4a4b4=70a4b4.因?yàn)?a+b)9的展開(kāi)式中有10項(xiàng),所以中間兩項(xiàng)的二項(xiàng)式系數(shù)最大,這兩項(xiàng)分別為C_9^4a5b4=126a5b4,C_9^5a4b5=126a4b5.答案:1.70a4b4 126a5b4與126a4b5 2. A=C_n^0+C_n^2+C_n^4+…與B=C_n^1+C_n^3+C_n^5+…的大小關(guān)系是( )A.A>B B.A=B C.A<B D.不確定 解析:∵(1+1)n=C_n^0+C_n^1+C_n^2+…+C_n^n=2n,(1-1)n=C_n^0-C_n^1+C_n^2-…+(-1)nC_n^n=0,∴C_n^0+C_n^2+C_n^4+…=C_n^1+C_n^3+C_n^5+…=2n-1,即A=B.答案:B
人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的方差教學(xué)設(shè)計(jì)
3.下結(jié)論.依據(jù)均值和方差做出結(jié)論.跟蹤訓(xùn)練2. A、B兩個(gè)投資項(xiàng)目的利潤(rùn)率分別為隨機(jī)變量X1和X2，根據(jù)市場(chǎng)分析， X1和X2的分布列分別為X1 2% 8% 12% X2 5% 10%P 0.2 0.5 0.3 P 0.8 0.2求：(1)在A、B兩個(gè)項(xiàng)目上各投資100萬(wàn)元， Y1和Y2分別表示投資項(xiàng)目A和B所獲得的利潤(rùn)，求方差D(Y1)和D(Y2)；(2)根據(jù)得到的結(jié)論，對(duì)于投資者有什么建議？ 解：(1)題目可知，投資項(xiàng)目A和B所獲得的利潤(rùn)Y1和Y2的分布列為：Y1 2 8 12 Y2 5 10P 0.2 0.5 0.3 P 0.8 0.2所以 ;; 解：(2) 由(1)可知 ，說(shuō)明投資A項(xiàng)目比投資B項(xiàng)目期望收益要高；同時(shí) ，說(shuō)明投資A項(xiàng)目比投資B項(xiàng)目的實(shí)際收益相對(duì)于期望收益的平均波動(dòng)要更大.因此，對(duì)于追求穩(wěn)定的投資者，投資B項(xiàng)目更合適;而對(duì)于更看重利潤(rùn)并且愿意為了高利潤(rùn)承擔(dān)風(fēng)險(xiǎn)的投資者，投資A項(xiàng)目更合適.
人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的均值教學(xué)設(shè)計(jì)
對(duì)于離散型隨機(jī)變量，可以由它的概率分布列確定與該隨機(jī)變量相關(guān)事件的概率。但在實(shí)際問(wèn)題中，有時(shí)我們更感興趣的是隨機(jī)變量的某些數(shù)字特征。例如，要了解某班同學(xué)在一次數(shù)學(xué)測(cè)驗(yàn)中的總體水平，很重要的是看平均分；要了解某班同學(xué)數(shù)學(xué)成績(jī)是否“兩極分化”則需要考察這個(gè)班數(shù)學(xué)成績(jī)的方差。我們還常常希望直接通過(guò)數(shù)字來(lái)反映隨機(jī)變量的某個(gè)方面的特征，最常用的有期望與方差.二、 探究新知探究1.甲乙兩名射箭運(yùn)動(dòng)員射中目標(biāo)靶的環(huán)數(shù)的分布列如下表所示：如何比較他們射箭水平的高低呢？環(huán)數(shù)X 7 8 9 10甲射中的概率 0.1 0.2 0.3 0.4乙射中的概率 0.15 0.25 0.4 0.2類(lèi)似兩組數(shù)據(jù)的比較,首先比較擊中的平均環(huán)數(shù),如果平均環(huán)數(shù)相等，再看穩(wěn)定性.假設(shè)甲射箭n次，射中7環(huán)、8環(huán)、9環(huán)和10環(huán)的頻率分別為：甲n次射箭射中的平均環(huán)數(shù)當(dāng)n足夠大時(shí)，頻率穩(wěn)定于概率，所以x穩(wěn)定于7×0.1+8×0.2+9×0.3+10×0.4=9.即甲射中平均環(huán)數(shù)的穩(wěn)定值(理論平均值)為9,這個(gè)平均值的大小可以反映甲運(yùn)動(dòng)員的射箭水平.同理，乙射中環(huán)數(shù)的平均值為7×0.15+8×0.25+9×0.4+10×0.2=8.65.
新人教版高中英語(yǔ)選修2Unit 4 Reading and thinking教學(xué)設(shè)計(jì)
【詞匯精講】highlight n.最好或最精彩的部分 vt.突出;強(qiáng)調(diào);使醒目One of the highlights of the trip was seeing the Taj Mahal.這次旅行的亮點(diǎn)之一是參觀泰姬陵。Your resume should highlight your skills and achievements.你的簡(jiǎn)歷應(yīng)該突出你的技能和成就。The report highlights the major problems facing society today.報(bào)告強(qiáng)調(diào)了當(dāng)今社會(huì)所面臨的主要問(wèn)題。I’ve highlighted the important passages in yellow.我用黃色標(biāo)出了重要段落。7.Edmonton is freezing cold in winter,with daily temperatures averaging -10 ℃.埃德蒙頓冬季寒冷,日平均氣溫為-10°C。【詞匯精講】freezing adj.極冷的;冰凍的Leave a basin of water outside in freezing weather.在冰凍的天氣里,放一盆水在室外。It’s freezing cold outside so wear a warm coat.外面超冷的,所以穿一個(gè)暖和一點(diǎn)的外套吧。8.It was not until 9:30 a.m.that they finally reached the capital of Ontario,Toronto.直到上午9時(shí)30分,他們才終于到達(dá)多倫多的首府安大略省?！揪涫狡饰觥勘揪涫且粋€(gè)強(qiáng)調(diào)句,強(qiáng)調(diào)的是句子的時(shí)間狀語(yǔ)until 9:30。含有not...until...的句子的強(qiáng)調(diào)句為It is not until...that...,that后面的句子要用肯定形式。It was not until then that I suddenly realized nobody was happier than I was.直到那時(shí)我才突然意識(shí)到?jīng)]有人比我更幸福了。
新人教版高中英語(yǔ)選修2Unit 3 Learning about Language教學(xué)設(shè)計(jì)
1. We'll need ten months at least to have the restaurant decorated.2.Some traditional Chinese dishes from before the Ming Dynasty are still popular today.3.My grandpa's breakfast mainly includes whole grain biscuits and a glass of milk.4.People in this area would eat nearly a kilo of cheese per week.5. We enjoyed a special dinner in a fancy restaurant where the waiters all wore attractive suits.6. He prefers this brand of coffee which, as he said, has an unusually good flavor.Key:1. at a minimum 2. prior to3. consist of4. consume5. elegant6. exceptionalStep 5：Familiarize yourself with some food idioms by matching the meaning on the right with the colored words on the left.1.Public concern for the health of farm animals has mushroomed in the UK2.Anderson may be young but he's certainly rolling to doing dough!3.George is a popular lecturer. He often peppers his speech with jokes.4.As the person to bring home the bacon, he needs to find a stable job.5 He is often regarded as a ham actor for his over emphasized facial expressions. The media reported that these companies had treated pollution as a hot potato. 6.The media reported that these companies had treated pollution as a hot potato.7.Don't worry about the test tomorrow. It's going to be a piece of cake!8. It's best to fold the swimming ring when it is as flat as a pancake.A. completely flatB. something that is very easy to do C.an issue that is hard to deal withD.to include large numbers of somethingE.to earn on e's living to support a familyF. wealthyG.to rapidly increase in numberH. an actor who performs badly, especially by over emphasizing emotions
新人教版高中英語(yǔ)選修2Unit 2 Reading and thinking教學(xué)設(shè)計(jì)
Her tutor told her to acknowledge __________ other people had said if she cited their ideas, and advised her _______（read） lots of information in order to form __________wise opinion of her own.Now halfway __________ her exchange year, Xie Lei felt much more at home in the UK. She said __________ (engage) in British culture had helped and that she had been__________ (involve) in social activities. She also said while learning about business, she was acting as a cultural messenger __________（build） a bridge between the two countries. keys:Xie Lei, a 19yearold Chinese student, said goodbye to her family and friends in China and boarded (board) a plane for London six months ago in order to get a business qualification. She was ambitious(ambition) to set up a business after graduation. It was the first time that she had left (leave) home.At first, Xie Lei had to adapt to life in a different country. She chose to live with a host family, who can help with her adaptation (adapt) to the new culture. When she missed home, she felt comforted (comfort) to have a second family. Also Xie Lei had to satisfy academic requirements. Her tutor told her to acknowledge what other people had said if she cited their ideas, and advised her to read lots of information in order to form a wise opinion of her own.Now halfway through her exchange year, Xie Lei felt much more at home in the UK. She said engaging (engage) in British culture had helped and that she had been involved (involve) in social activities. She also said while learning about business, she was acting as a cultural messenger building a bridge between the two countries.
新人教版高中英語(yǔ)選修2Unit 3 Reading for writing教學(xué)設(shè)計(jì)
The theme of this part is to write an article about healthy diet. Through reading and writing activities, students can accumulate knowledge about healthy diet, deepen their understanding of the theme of healthy diet, and reflect on their own eating habits. This text describes the basic principles of healthy diet. The author uses data analysis, definition, comparison, examples and other methods. It also provides a demonstration of the use of conjunctions, which provides important information reference for students to complete the next collaborative task, writing skills, vivid language materials and expressions.1. Teach Ss to learn and skillfully use the new words learned from the text.2. Develop students’ ability to understand, extract and summarize information.3. Guide students to understand the theme of healthy diet and reflect on their own eating habits.4. To guide students to analyze and understand the reading discourse from the aspects of theme content, writing structure, language expression, etc., 5. Enable Ss to write in combination with relevant topics and opinions, and to talk about their eating habits.1. Guide students to analyze and understand the reading discourse from the aspects of theme content, writing structure, language expression, etc.2. Enable them to write in combination with relevant topics and opinions, and to talk about their eating habits.3. Guide the students to use the cohesive words correctly, strengthen the textual cohesion, and make the expression fluent and the thinking clear.Step1: Warming upbrainstorm some healthy eating habits.1.Eat slowly.2.Don’t eat too much fat or sugar.3.Eat healthy food.4.Have a balanced diet.Step2: Read the passage and then sum up the main idea of each paragraph.
新人教版高中英語(yǔ)選修2Unit 2 Reading for writing教學(xué)設(shè)計(jì)
The theme of this section is to express people's views on studying abroad. With the continuous development of Chinese economic construction, especially the general improvement of people's living standards, the number of Chinese students studying abroad at their own expense is on the rise. Many students and parents turn their attention to the world and regard studying abroad as an effective way to improve their quality, broaden their horizons and master the world's advanced scientific knowledge, which is very important for the fever of going abroad. Studying abroad is also an important decision made by a family for their children. Therefore, it is of great social significance to discuss this issue. The theme of this section is the column discussion in the newspaper: the advantages and disadvantages of studying abroad. The discourse is about two parents' contribution letters on this issue. They respectively express their own positions. One thinks that the disadvantages outweigh the advantages, and the other thinks that the advantages outweigh the disadvantages. The two parents' arguments are well founded and logical. It is worth noting that the two authors do not express their views on studying abroad from an individual point of view, but from a national or even global point of view. These two articles have the characteristics of both letters and argumentative essays1.Guide the students to read these two articles, and understand the author's point of view and argument ideas2.Help the students to summarize the structure and writing methods of argumentative writing, and guides students to correctly understand the advantages and disadvantages of studying abroad3.Cultivate students' ability to analyze problems objectively, comprehensively and deeply
新人教版高中英語(yǔ)選修2Unit 2 Using langauge-Listening教學(xué)設(shè)計(jì)
? B: Absolutely! Getting involved with Chinese cultural activities there definitely helped a lot. I got to practice my Chinese on a daily basis, and I could learn how native Chinese speakers spoke.? A: What do you feel is your biggest achievement?? B: Learning Chinese characters! I have learnt about 1,500 so far. When I first started, I didn't think it was even going to be possible to learn so many, but now I find that I can read signs, menus, and even some easy newspaper articles.? A: What are you most keen on?? B: I've really become keen on learning more about the Chinese culture, in particular Chinese calligraphy. As I have learnt Chinese characters, I have developed a great appreciation for their meaning. I want to explore Chinese characters by learning how to write them in a more beautiful way. ? A: Finally, what do you want to say to anyone interested in learning Chinese?? I have really become keen on learning more about the Chinese culture, in particular Chinese Calligraphy. As I have learnt Chinese character, I have developed a great appreciation for their meaning. I want to explore Chinese characters by learning how to write them in a more beautiful way.? A: Finally, what do you want to say to anyone interested in learning Chinese?? B: I'd say, give it a shot! While some aspects may be difficult, it is quite rewarding and you will be happy that you tried.? A: Thanks for your time. ? B:You're welcome.
新人教版高中英語(yǔ)選修2Unit 4 Using langauge-Listening教學(xué)設(shè)計(jì)
The theme of the listening section is " talking about scenery and culture along a journey."The part is designed to further lead the students to understand Canadian natural geography and social environment, and integrated into the cultural contrast by mentioning the long train journey from Beijing to Moscow routes. On this basis, the part activates students related travel experience, lets the student serial dialogue, guides the student to explore further the pleasure and meaning of the long journey, and Chinese and foreign cultural comparison.The part also provides a framework for the continuation of the dialogue, which is designed to provide a framework for students to successfully complete their oral expressions, and to incorporate an important trading strategy to end the dialogue naturally.1. Help students to understand and master some common English idioms in the context, and experience the expression effect of English idioms.2. Guide the students to understand the identity of different people in the listening context, and finish the dialogue according to their own experience.3. Instruct the students to use appropriate language to express surprise and curiosity about space and place in the dialogue, and master the oral strategy of ending the dialogue naturally.1. Instruct students to grasp the key information and important details of the dialogue.2. Instruct students to conduct a similar talk on the relevant topic.
新人教版高中英語(yǔ)選修2Unit 5 Learning about Language教學(xué)設(shè)計(jì)
The purpose of this section of vocabulary exercises is to consolidate the key words in the first part of the reading text, let the students write the words according to the English definition, and focus on the detection of the meaning and spelling of the new words. The teaching design includes use English definition to explain words, which is conducive to improving students' interest in vocabulary learning, cultivating their sense of English language and thinking in English, and making students willing to use this method to better grasp the meaning of words, expand their vocabulary, and improve their ability of vocabulary application. Besides, the design offers more context including sentences and short passage for students to practice words flexibly.1. Guide students to understand and consolidate the meaning and usage of the vocabulary in the context, 2. Guide the students to use the unit topic vocabulary in a richer context3. Let the students sort out and accumulate the accumulated vocabulary, establishes the semantic connection between the vocabulary,4. Enable students to understand and master the vocabulary more effectivelyGuiding the Ss to use unit topic words and the sentence patterns in a richer context.Step1: Read the passage about chemical burns and fill in the blanks with the correct forms of the words in the box.
新人教版高中英語(yǔ)選修2Unit 5 Using langauge-Listening教學(xué)設(shè)計(jì)
The theme of this section is to learn how to make emergency calls. Students should learn how to make emergency calls not only in China, but also in foreign countries in English, so that they can be prepared for future situations outside the home.The emergency telephone number is a vital hotline, which should be the most clear, rapid and effective communication with the acute operator.This section helps students to understand the emergency calls in some countries and the precautions for making emergency calls. Through the study of this section, students can accumulate common expressions and sentence patterns in this context. 1.Help students accumulate emergency telephone numbers in different countries and learn more about first aid2.Guide the students to understand the contents and instructions of the telephone, grasp the characteristics of the emergency telephone and the requirements of the emergency telephone.3.Guide students to understand the first aid instructions of the operators.4.Enable Ss to make simulated emergency calls with their partners in the language they have learned1. Instruct students to grasp the key information and important details of the dialogue.2. Instruct students to conduct a similar talk on the relevant topic.Step1:Look and discuss:Match the pictures below to the medical emergencies, and then discuss the questions in groups.
人教版高中數(shù)學(xué)選修3排列與排列數(shù)教學(xué)設(shè)計(jì)
4.有8種不同的菜種,任選4種種在不同土質(zhì)的4塊地里,有 種不同的種法. 解析:將4塊不同土質(zhì)的地看作4個(gè)不同的位置,從8種不同的菜種中任選4種種在4塊不同土質(zhì)的地里,則本題即為從8個(gè)不同元素中任選4個(gè)元素的排列問(wèn)題,所以不同的種法共有A_8^4 =8×7×6×5=1 680(種).答案:1 6805.用1、2、3、4、5、6、7這7個(gè)數(shù)字組成沒(méi)有重復(fù)數(shù)字的四位數(shù).(1)這些四位數(shù)中偶數(shù)有多少個(gè)?能被5整除的有多少個(gè)?(2)這些四位數(shù)中大于6 500的有多少個(gè)?解:(1)偶數(shù)的個(gè)位數(shù)只能是2、4、6,有A_3^1種排法,其他位上有A_6^3種排法,由分步乘法計(jì)數(shù)原理,知共有四位偶數(shù)A_3^1·A_6^3=360(個(gè));能被5整除的數(shù)個(gè)位必須是5,故有A_6^3=120(個(gè)).(2)最高位上是7時(shí)大于6 500,有A_6^3種,最高位上是6時(shí),百位上只能是7或5,故有2×A_5^2種.由分類(lèi)加法計(jì)數(shù)原理知,這些四位數(shù)中大于6 500的共有A_6^3+2×A_5^2=160(個(gè)).
人教版高中數(shù)學(xué)選修3超幾何分布教學(xué)設(shè)計(jì)
探究新知問(wèn)題1：已知100件產(chǎn)品中有8件次品，現(xiàn)從中采用有放回方式隨機(jī)抽取4件．設(shè)抽取的4件產(chǎn)品中次品數(shù)為X，求隨機(jī)變量X的分布列.（1）：采用有放回抽樣，隨機(jī)變量X服從二項(xiàng)分布嗎？采用有放回抽樣，則每次抽到次品的概率為0.08，且各次抽樣的結(jié)果相互獨(dú)立,此時(shí)X服從二項(xiàng)分布,即X～B(4，0.08).（2）：如果采用不放回抽樣，抽取的4件產(chǎn)品中次品數(shù)X服從二項(xiàng)分布嗎？若不服從，那么X的分布列是什么？不服從，根據(jù)古典概型求X的分布列.解：從100件產(chǎn)品中任取4件有 C_100^4 種不同的取法，從100件產(chǎn)品中任取4件，次品數(shù)X可能取0,1,2,3,4.恰有k件次品的取法有C_8^k C_92^(4-k)種.一般地，假設(shè)一批產(chǎn)品共有N件，其中有M件次品．從N件產(chǎn)品中隨機(jī)抽取n件(不放回），用X表示抽取的n件產(chǎn)品中的次品數(shù)，則X的分布列為P(X＝k）＝CkM Cn－kN－M CnN ，k＝m，m＋1，m＋2，…，r.其中n，N，M∈N*，M≤N，n≤N，m＝max{0，n－N＋M}，r＝min{n，M}，則稱隨機(jī)變量X服從超幾何分布．
人教版高中數(shù)學(xué)選修3條件概率教學(xué)設(shè)計(jì)
(2)方法一:第一次取到一件不合格品,還剩下99件產(chǎn)品,其中有4件不合格品,95件合格品,于是第二次又取到不合格品的概率為4/99,由于這是一個(gè)條件概率,所以P(B|A)=4/99.方法二:根據(jù)條件概率的定義,先求出事件A,B同時(shí)發(fā)生的概率P(AB)=(C_5^2)/(C_100^2 )=1/495,所以P(B|A)=(P"(" AB")" )/(P"(" A")" )=(1/495)/(5/100)=4/99.6.在某次考試中,要從20道題中隨機(jī)地抽出6道題,若考生至少答對(duì)其中的4道題即可通過(guò);若至少答對(duì)其中5道題就獲得優(yōu)秀.已知某考生能答對(duì)其中10道題,并且知道他在這次考試中已經(jīng)通過(guò),求他獲得優(yōu)秀成績(jī)的概率.解:設(shè)事件A為“該考生6道題全答對(duì)”,事件B為“該考生答對(duì)了其中5道題而另一道答錯(cuò)”,事件C為“該考生答對(duì)了其中4道題而另2道題答錯(cuò)”,事件D為“該考生在這次考試中通過(guò)”,事件E為“該考生在這次考試中獲得優(yōu)秀”,則A,B,C兩兩互斥,且D=A∪B∪C,E=A∪B,由古典概型的概率公式及加法公式可知P(D)=P(A∪B∪C)=P(A)+P(B)+P(C)=(C_10^6)/(C_20^6 )+(C_10^5 C_10^1)/(C_20^6 )+(C_10^4 C_10^2)/(C_20^6 )=(12" " 180)/(C_20^6 ),P(E|D)=P(A∪B|D)=P(A|D)+P(B|D)=(P"(" A")" )/(P"(" D")" )+(P"(" B")" )/(P"(" D")" )=(210/(C_20^6 ))/((12" " 180)/(C_20^6 ))+((2" " 520)/(C_20^6 ))/((12" " 180)/(C_20^6 ))=13/58,即所求概率為13/58.
人教版高中數(shù)學(xué)選修3正態(tài)分布教學(xué)設(shè)計(jì)
3.某縣農(nóng)民月均收入服從N(500,202)的正態(tài)分布,則此縣農(nóng)民月均收入在500元到520元間人數(shù)的百分比約為 . 解析:因?yàn)樵率杖敕恼龖B(tài)分布N(500,202),所以μ=500,σ=20,μ-σ=480,μ+σ=520.所以月均收入在[480,520]范圍內(nèi)的概率為0.683.由圖像的對(duì)稱性可知,此縣農(nóng)民月均收入在500到520元間人數(shù)的百分比約為34.15%.答案:34.15%4.某種零件的尺寸ξ(單位:cm)服從正態(tài)分布N(3,12),則不屬于區(qū)間[1,5]這個(gè)尺寸范圍的零件數(shù)約占總數(shù)的 . 解析:零件尺寸屬于區(qū)間[μ-2σ,μ+2σ],即零件尺寸在[1,5]內(nèi)取值的概率約為95.4%,故零件尺寸不屬于區(qū)間[1,5]內(nèi)的概率為1-95.4%=4.6%.答案:4.6%5. 設(shè)在一次數(shù)學(xué)考試中,某班學(xué)生的分?jǐn)?shù)X~N(110,202),且知試卷滿分150分,這個(gè)班的學(xué)生共54人,求這個(gè)班在這次數(shù)學(xué)考試中及格(即90分及90分以上)的人數(shù)和130分以上的人數(shù).解:μ=110,σ=20,P(X≥90)=P(X-110≥-20)=P(X-μ≥-σ),∵P(X-μσ)≈2P(X-μ130)=P(X-110>20)=P(X-μ>σ),∴P(X-μσ)≈0.683+2P(X-μ>σ)=1,∴P(X-μ>σ)=0.158 5,即P(X>130)=0.158 5.∴54×0.158 5≈9(人),即130分以上的人數(shù)約為9人.