Step 4: Listen again and decide if the following statements are true (T) or false (F).1 It was the first time Chen Liyan's story was reported. T口 F口2 Chen found 10,000 yuan in a small plastic bag in Taiyuan railway station口 F口3 Wang Zheng apologized to Chen because he couldn't offer her more money. T口 F口4 Chen took out a large loan to cure her daughter, T口 F口5 Wang set up a fundraising website for Chen's daughter after Chen told him about her situation. T口 F口Step 5:After listening, discuss the questions.1 What kind of person do you think Chen Liyan is?Chen Liyan is generous and honest because she returned a large sum of money to the owner.2 Did Chen return the money because she didn't need it?No. She returned the money because it was the right thing to do. Evidence for this is that she refused to accept the reward money because she felt that it had not been earned. 3 Is it common for people to do what Chen did?It depends on the culture. In some countries it is quite common to return money that has been found. In other countries, people believe "Finders are keepers!" 4 How did Wang Zheng feel about the return of his money?He must have been very happy and relieved to have gotten his money back. We know this because he thanked Chen repeatedly and even offered her a reward.5 Why did Ma Dongbao tell Wang about Chen's family?He must have had great sympathy for Chen and her daughter and wanted to help them.'We know this because he arranged help for them. 6 How did the news reporter feel about Chen's actions?The news reporter felt that it showed that money wasn't the most important thing in life. We know this because the reporter told us that this is what Chen believes. and then said, “that's a great attitude to take."
【設(shè)計(jì)意圖】 基于上述分析,學(xué)生總結(jié)新聞故事語篇類型的特征,即標(biāo)題的省略性、導(dǎo)語的概括性、數(shù)據(jù)的支撐性和引語的重要性。在此過程中,學(xué)生對新聞故事語篇類型有了更深層次的了解,對于學(xué)生閱讀和寫作具有重要意義。Activity 7: Discussing to make a writing outline.本活動(dòng)為實(shí)現(xiàn)課時(shí)目標(biāo)3。1.Discuss and make an outline.Ask students to discuss in groups of four and make their own writing outline.To celebrate the 70th anniversary of the People’s Republic of China, our school newspaper starts a new column about “People of Achievement”. You plan to write a news story about one of the winners of the Medal of the Republic in 2019, including Yu Min, Shen Jilan, Sun Jiadong, Li Yannian, Zhang Fuqing, Yuan Longping, Huang Xuhua and Tu Youyou.【設(shè)計(jì)意圖】 教師創(chuàng)設(shè)情境,即為慶祝新中國成立70周年,校報(bào)新增有關(guān)卓有成就人物的欄目,你將從共和國勛章獲得者中,選擇一位寫一篇新聞故事,向該欄目投稿。學(xué)生以小組合作形式,展開討論,并寫出新聞故事框架,有助于學(xué)生課后收集人物信息,撰寫新聞故事。
[2] An important breakthrough…was… [3] Another innovation was … [4] the emphasis increasingly shifted from…to… [5] New ideas and values gradually replaced… [6] While his paintings still had religious themes… … T: All these expressions serve to show how Western painting has developed. Some of them share similar structure but with varied use of words, which makes the text vivid and more readable. 【設(shè)計(jì)意圖】主題類語言整理有助于學(xué)生類化語言應(yīng)用,提高語言輸出的豐富性。處理完文本內(nèi)容信息后,進(jìn)入語篇信息處理,進(jìn)行主題相關(guān)的詞塊歸類。引導(dǎo)學(xué)生快速閱讀,尋找表達(dá)相同主題(發(fā)展或者藝術(shù))的詞和短語,再根據(jù)詞性、用法和結(jié)構(gòu)進(jìn)行歸類,儲備主題相關(guān)詞匯,豐富語言儲備,提升語言素養(yǎng)。 Assignment: Go online to gather more information about Chinese painting and write a short history of it. 【設(shè)計(jì)意圖】結(jié)合所學(xué),遷移運(yùn)用,根據(jù)實(shí)際語境,進(jìn)行模仿性運(yùn)用。在此過程中,學(xué)生嘗試借鑒已學(xué)的語言、內(nèi)容、語篇結(jié)構(gòu)和寫作手法來建構(gòu)新文本,實(shí)現(xiàn)語篇輸出,同時(shí)關(guān)注中西藝術(shù)文化的差別,加深對優(yōu)秀文化的認(rèn)同,培養(yǎng)文化意識。
2. Explore the significance of the establishment of Sarek National Park.Q1: Which event is the most important one in the park’s history?Ss: The establishment of Sarek national park in 1909 is the most important one.Q2: Is it worth making a place like Sarek a national park? Give your reasons.Ss: Yes. In this way, the place can be kept in its natural state and natural beauties and other rare and valuable resources can be preserved instead of being destroyed by endless exploitation driven by profits.Q3: How does the writer organize his introduction to the history of Sarek?Ss: The writer organizes his introduction in the sequence of time, using time indicators such as “used to”, “around 9,000 years ago”, “soon after”, “following the reindeer”, and “in 1909”.Q4: What is the feature of the language used to introduce the history of the park?Ss: The introduction to the park is to provide facts, using time indicators to organize the events. Sentences starts with “third person” and passive voice is used more often, feeling objective.【設(shè)計(jì)意圖】學(xué)生尋找和梳理公園歷史上的重要事件,體會人與自然的和諧關(guān)系,評鑒介紹性語言的特點(diǎn)?!竞诵乃仞B(yǎng)提升點(diǎn)】發(fā)展自主提取、梳理文本信息能力,訓(xùn)練邏輯思維和高階思維。Activity 3: Highlighting the secret of the text
本閱讀材料的話題是交際中的肢體語言,作者從三個(gè)方面講述了肢體語言的特征與作用,通過主題句和舉例闡述的方式讓讀者了解不同文化中肢體語言的相同或者不同的意義,并從更抽象、概括的維度深入認(rèn)識肢體語言的特點(diǎn),理解肢體語言的作用?;谥w語言的特點(diǎn),作者提醒讀者在與人交流中,尤其是當(dāng)文化背景有差異的時(shí)候,要使用得體的肢體語言,尊重、理解和包容不同的文化,進(jìn)行有效、有素養(yǎng)的溝通。文本共由六個(gè)段落組成,篇章結(jié)構(gòu)為“總—分”。第一段用簡練的語言引出了話題,并且從我們自身表達(dá)的需要和了解他人感受兩個(gè)角度講述了肢體語言的作用。第二段闡述了肢體語言的第一個(gè)重要特點(diǎn)——肢體語言在不同的文化中有不同的內(nèi)涵——這也是文中寫作篇幅最大的一個(gè)要點(diǎn),最為重要。通過講述肢體語言的這一特點(diǎn),作者向讀者傳遞了要尊重不同的文化、要使用與所在文化相宜的肢體語言。
1. 完成文本主要信息填空(斜體字部分設(shè)空):As a witness to farmers’ poor harvests and even a severe shortage of food, Yuan Longping was determined to devote his life to tackling this crisis. After graduation, he realized that what farmers needed most was to boost yields in the fields. Yuan was convinced that the answer lay in the creation of hybrid rice, one characteristic of which is that it usually achieve higher output than conventional crops. However, it was no easy job. The first difficulty he needed to overcome was scientists’ general assumption that this could not be done. Through trial and error, Yuan managed to generate this incredible crop. It is estimated that about 60 percent of domestic rice consumption in China was comprised of crops generated from Yuan’s hybrid strains. His innovation has enabled Chinese farmers to considerably expand their output and helped feed the world. Unwilling to retire early to a life of leisure and unconcerned about celebrity or fortune, Yuan continues to turn one vision after another into realities.2. 模仿寫作:Do some research via the Internet and introduce another agricultural scientist, Chen Risheng(陳日勝), using the structure, expressions and writing techniques you have learnt from the text “A Pioneer for All People”.【設(shè)計(jì)意圖】任務(wù)1是對文本內(nèi)容和詞匯學(xué)習(xí)成效的檢測。任務(wù)2借助文本中學(xué)到的詞匯和寫作手法仿寫另一位科學(xué)家,提升學(xué)生遷移運(yùn)用詞匯、文體結(jié)構(gòu)和寫作方法的能力。
點(diǎn)撥:旅游地旅游資源的特色不同,可以安排的旅游活動(dòng)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(diǎn)的特色等情況。旅游地的時(shí)空可達(dá)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(fèi)用和時(shí)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(shí)間過長、旅行費(fèi)用過高,經(jīng)濟(jì)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(yuǎn),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(biāo)準(zhǔn)、導(dǎo)游服務(wù)、旅行費(fèi)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(dá)拉宮和圖5.4云南香格里拉兩幅圖片顯示了西藏布達(dá)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(diǎn)。
Activity 4: Figuring out the structure and the writing purpose 本活動(dòng)為實(shí)現(xiàn)課時(shí)目標(biāo)2。 1.Read Paragraph 6 and think about its main idea and the writer’s writing purpose. Q1: If you were the author, how would you end your article? “For young people, there is plenty of time to change bad habits. However, there is no “magic pill” or delete button that will help you; you have to think about your bad habits and decide on some changes. You have the power to build a happy and healthy life full of good habits!” Q2: What is Paragraph 6 mainly about? (Possible answer: to appeal to young people including teenagers to change bad habits and live a happy and healthy life.) 2.Think about the writer’s writing purpose and share opinions. Q1: What is the writing purpose? Work in pairs and figure it out. (Possible answer: On the one hand, the passage is written to help teenagers change their bad habits and live a healthy lifestyle. On the other hand, it provides us with a scientific way to identify and analyse our problems objectively, thus strengthening our resolve to tackle the seemingly common yet tough problems in our lives.) 【設(shè)計(jì)意圖】 步驟1旨在預(yù)測和驗(yàn)證文章最后一段主要內(nèi)容,梳理完整的語篇結(jié)構(gòu),步驟2旨在思考和討論作者的寫作目的。教師也可根據(jù)學(xué)生課堂反應(yīng)情況融入對語篇人稱多次轉(zhuǎn)換的思考。
幫助學(xué)生通過討論與對主題的提升,反思自己的旅游方式,以便做出更優(yōu)化的安排,在今后的旅程中有更多的收益。 Activity 2: Further discussion of the 6 elements above and supplement of more background knowledge 本活動(dòng)為實(shí)現(xiàn)課時(shí)教學(xué)目標(biāo)2。 1.Target Q: The writer’s clear target of traveling, meeting the people and experiencing the culture, is closely related to his major in social studies. Then what is social studies? Social studies is a part of a school or college curriculum concerned with the study of social relationships and the functioning of society and usually made up of courses in history, government, economics, civics, sociology, geography, and anthropology. (Dictionary by Merriam-Webster) Reflection: When you go out to travel, what targets do you usually have in mind? 2.Research Q: Suppose you are traveling to Hangzhou during the school holidays, how will you do research on the city? (surf the internet, read books or travel brochures, consult friends, ...) What information will you be interested to know? (location, iconic sites, local cuisines, interesting customs, shopping malls ...) 3.Abandonment To make the most of time, we have to learn to abandon so that we can accomplish our plan. What will you be interested in doing if you go to Hangzhou if you have a week’s time? What if you only have 2 days? 4~5. Venturing & Experiencing Q: What did he venture to do during the trip? What new experiences did he have? In Sydney: attend his first open-air barbecue, enjoy many different but yummy meals In Catherine: observe the life and customs of the aborigines appreciate their music & try the musical instruments: the didgeridoo
本活動(dòng)旨在落實(shí)課時(shí)目標(biāo)3。 The Student Union is looking for three students for a 3-week voluntary program in Guizhou province. The volunteers have got to be high school students, with a persevering personality and experiences in overcoming adversity. The volunteers need to stay, eat and teach with 20 pupils in a small school up on the hill of a village. There are no facilities but desks and a blackboard in the school. And there is no take-away food to be bought anywhere; the only way to feed yourself is to cook. You’re interested in applying. Write your application letter introducing what adversity you have ever overcome and how persevering you are as well as what you want to do when at work. Dear Student Union,【設(shè)計(jì)意圖】此任務(wù)旨在遷移一、二課時(shí)所學(xué),解決實(shí)際問題。學(xué)生對比自己經(jīng)歷過的挑戰(zhàn)或挫折,寫信給學(xué)生會申請前往貴州擔(dān)任短期支教教師,把個(gè)人以前是怎么戰(zhàn)勝挫折的經(jīng)過書寫出來。結(jié)合所學(xué),遷移創(chuàng)新,分析解決自身實(shí)際問題,在真實(shí)情境中學(xué)生通過仿寫進(jìn)行主題語言的精確輸出。完成任務(wù)的過程中,能較多地使用已學(xué)語言、內(nèi)容、結(jié)構(gòu)和寫作手法來描述自己面對挫折的處理方式、態(tài)度和應(yīng)有的品質(zhì),近一步激發(fā)學(xué)生樹立正確的價(jià)值觀,學(xué)會逆境出人才,堅(jiān)忍不拔,從容不迫,又做到謙讓、分享和合作。課后學(xué)生修正習(xí)作,再次提交。
本單元閱讀文本介紹了幾種簡單的英語詩歌形式,旨在讓學(xué)生能理解和欣賞英語詩歌的美,包括形式美、內(nèi)容美、意義美,培養(yǎng)審美情趣,并從作品的意義美中獲得積極的人生態(tài)度和價(jià)值觀念啟示。 該文本是一則典型的說明性文本,用簡單易懂的語言向英語詩歌的初學(xué)者們介紹了五種比較簡單的英語詩歌形式。文題“A Few Simple Forms of English Poems”是整個(gè)文本的核心話題。正文內(nèi)容共七段,按“總—分—總”建構(gòu)。第一段為總起段,概述了英語詩歌的創(chuàng)作原因以及主要特點(diǎn),涉及了形式、內(nèi)容、意義等方面賞析英語詩歌的幾個(gè)主要維度;第二段至第六段分別介紹了童謠、清單詩、五行詩、俳句和唐詩五種英語詩歌形式;第七段收尾,鼓勵(lì)讀者嘗試英語詩歌創(chuàng)作。 在進(jìn)行文本教學(xué)設(shè)計(jì)時(shí),要引導(dǎo)學(xué)生梳理關(guān)于與詩歌要素和詩歌賞析有關(guān)的話題類語言,既包括format、rhythm、subject、image等名詞,也包括have a strong rhythm、be made up of、contain、consist of、convey這樣的動(dòng)詞和動(dòng)詞短語。
本活動(dòng)旨在落實(shí)課時(shí)目標(biāo)3。 Think about the following questions and talk about your own attitude in pairs.Q1: As for this topic,what impresses you the most in the passage?Q2: What do you think of the future of China’s further exploration in sea? Are you in favor of the further exploration?Why or why not? 【設(shè)計(jì)意圖】該活動(dòng)是一個(gè)完全開放性的活動(dòng),每個(gè)學(xué)生都會有不同的答案。運(yùn)用遷移所學(xué),自由口頭表達(dá)自己對海洋探索的態(tài)度。對于中國海洋探索的未來,每個(gè)人的想法是不一樣的,有樂觀,有擔(dān)憂,有認(rèn)為值得投入,也有認(rèn)為不值得付出太大代價(jià),這里給學(xué)生自由表達(dá)的空間只要學(xué)會有支撐自己觀點(diǎn)的事實(shí)就可以了,進(jìn)一步培養(yǎng)學(xué)生批判性思維和正確的價(jià)值觀。 Assignment: 此任務(wù)旨在遷移一、二課時(shí)所學(xué),培養(yǎng)學(xué)生辯證分析問題的能力。 Write about your idea of the future of China’s sea exploration. And add your attitude towards the effort China have made in sea exploration. You’re expected to use the language and the writing technique learnt in the passage.
【核心素養(yǎng)提升點(diǎn)】學(xué)會將抽象信息進(jìn)行可視化表達(dá),提高信息處理能力和分析、推理等高階思維品質(zhì);在跨文化交際中學(xué)會以國際視野接受和包容不同的文化。 5.Read Paragraph 2, draw a mind map and answer the questions. Q1:What did Jo learn about Tombe’s life? Q2:What kind of life do the natives lead? Read paragraph 2-5 and draw a mind-map. (Focus on accommodation, possession, diet and belief) 【設(shè)計(jì)意圖】引導(dǎo)學(xué)生利用思維導(dǎo)圖和問題鏈等形式來厘清當(dāng)?shù)厝说纳罘绞?,更好地處理和歸納信息 【核心素養(yǎng)提升點(diǎn)】提高信息處理能力、分析和歸納能力,包容異國文化、擴(kuò)展國際視野。 6.Read Paragraph 3 and answer the questions. Q1:What was Jo’s feeling upon arriving her own home? Q2:Why would she feel that way? Q3:Do you think “It was such a privilege to have spent a day with Tombe’s family”? 【設(shè)計(jì)意圖】通過提問,讓學(xué)生理解Jo的苦并快樂的心情,并通過對“It was such a privilege to have spent a day with Tombe’s family”這句話的理解,體驗(yàn)志愿者生活的偉大。 【核心素養(yǎng)提升點(diǎn)】學(xué)會對信息的綜合和歸納,從而理解作者所表達(dá)的觀點(diǎn)。 Activity4: Summarize the change of Jo's feelings
本單元閱讀文本向中學(xué)生推薦職業(yè)能力測試(Career Aptitude Test),旨在建議學(xué)生利用職業(yè)傾向測試來發(fā)現(xiàn)自己更感興趣、更有潛力的學(xué)習(xí)或職業(yè)方向,并規(guī)劃自己的未來職業(yè)。 本文采用了建議性文本,全篇從職業(yè)生涯的重要意義講起,針對中學(xué)生對職業(yè)規(guī)劃比較迷茫的現(xiàn)狀,提出了職業(yè)傾向測試這一建議。全文共七段,其中第一段和第二段為第一部分,其余五段為第二部分。第一部分論述職業(yè)的重要性和職業(yè)生涯規(guī)劃的最佳時(shí)間是在校期間,第二部分提出解決職業(yè)選擇困惑可以通過完成職業(yè)能力測試,介紹了不同種類的職業(yè)傾向測試,結(jié)合圖表詳細(xì)說明其中一種操作步驟,并提醒職業(yè)建議也基于學(xué)歷和經(jīng)驗(yàn),最后一段概括論述,建議學(xué)生通過職業(yè)能力測試這一有效的工具,找到自己真正熱愛的事物。 在文本教學(xué)設(shè)計(jì)時(shí),要幫助學(xué)生梳理有關(guān)職業(yè)的話題語言。閱讀策略層面,指導(dǎo)學(xué)生通過學(xué)習(xí)圖表和圖形,在有限的空間內(nèi)獲取廣泛信息,如閱讀圖表標(biāo)題,圖表上的標(biāo)簽,X軸Y軸上的數(shù)據(jù)所指。
新知探究我們知道,等差數(shù)列的特征是“從第2項(xiàng)起,每一項(xiàng)與它的前一項(xiàng)的差都等于同一個(gè)常數(shù)” 。類比等差數(shù)列的研究思路和方法,從運(yùn)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(shí)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(xì)菌每20 min 就通過分裂繁殖一代,那么一個(gè)這種細(xì)菌從第1次分裂開始,各次分裂產(chǎn)生的后代個(gè)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
高斯(Gauss,1777-1855),德國數(shù)學(xué)家,近代數(shù)學(xué)的奠基者之一. 他在天文學(xué)、大地測量學(xué)、磁學(xué)、光學(xué)等領(lǐng)域都做出過杰出貢獻(xiàn). 問題1:為什么1+100=2+99=…=50+51呢?這是巧合嗎?試從數(shù)列角度給出解釋.高斯的算法:(1+100)+(2+99)+…+(50+51)= 101×50=5050高斯的算法實(shí)際上解決了求等差數(shù)列:1,2,3,…,n,"… " 前100項(xiàng)的和問題.等差數(shù)列中,下標(biāo)和相等的兩項(xiàng)和相等.設(shè) an=n,則 a1=1,a2=2,a3=3,…如果數(shù)列{an} 是等差數(shù)列,p,q,s,t∈N*,且 p+q=s+t,則 ap+aq=as+at 可得:a_1+a_100=a_2+a_99=?=a_50+a_51問題2: 你能用上述方法計(jì)算1+2+3+… +101嗎?問題3: 你能計(jì)算1+2+3+… +n嗎?需要對項(xiàng)數(shù)的奇偶進(jìn)行分類討論.當(dāng)n為偶數(shù)時(shí), S_n=(1+n)+[(2+(n-1)]+?+[(n/2+(n/2-1)]=(1+n)+(1+n)…+(1+n)=n/2 (1+n) =(n(1+n))/2當(dāng)n為奇數(shù)數(shù)時(shí), n-1為偶數(shù)
新知探究國際象棋起源于古代印度.相傳國王要獎(jiǎng)賞國際象棋的發(fā)明者,問他想要什么.發(fā)明者說:“請?jiān)谄灞P的第1個(gè)格子里放上1顆麥粒,第2個(gè)格子里放上2顆麥粒,第3個(gè)格子里放上4顆麥粒,依次類推,每個(gè)格子里放的麥粒都是前一個(gè)格子里放的麥粒數(shù)的2倍,直到第64個(gè)格子.請給我足夠的麥粒以實(shí)現(xiàn)上述要求.”國王覺得這個(gè)要求不高,就欣然同意了.假定千粒麥粒的質(zhì)量為40克,據(jù)查,2016--2017年度世界年度小麥產(chǎn)量約為7.5億噸,根據(jù)以上數(shù)據(jù),判斷國王是否能實(shí)現(xiàn)他的諾言.問題1:每個(gè)格子里放的麥粒數(shù)可以構(gòu)成一個(gè)數(shù)列,請判斷分析這個(gè)數(shù)列是否是等比數(shù)列?并寫出這個(gè)等比數(shù)列的通項(xiàng)公式.是等比數(shù)列,首項(xiàng)是1,公比是2,共64項(xiàng). 通項(xiàng)公式為〖a_n=2〗^(n-1)問題2:請將發(fā)明者的要求表述成數(shù)學(xué)問題.
我們知道數(shù)列是一種特殊的函數(shù),在函數(shù)的研究中,我們在理解了函數(shù)的一般概念,了解了函數(shù)變化規(guī)律的研究內(nèi)容(如單調(diào)性,奇偶性等)后,通過研究基本初等函數(shù)不僅加深了對函數(shù)的理解,而且掌握了冪函數(shù),指數(shù)函數(shù),對數(shù)函數(shù),三角函數(shù)等非常有用的函數(shù)模型。類似地,在了解了數(shù)列的一般概念后,我們要研究一些具有特殊變化規(guī)律的數(shù)列,建立它們的通項(xiàng)公式和前n項(xiàng)和公式,并應(yīng)用它們解決實(shí)際問題和數(shù)學(xué)問題,從中感受數(shù)學(xué)模型的現(xiàn)實(shí)意義與應(yīng)用,下面,我們從一類取值規(guī)律比較簡單的數(shù)列入手。新知探究1.北京天壇圜丘壇,的地面有十板布置,最中間是圓形的天心石,圍繞天心石的是9圈扇環(huán)形的石板,從內(nèi)到外各圈的示板數(shù)依次為9,18,27,36,45,54,63,72,81 ①2.S,M,L,XL,XXL,XXXL型號的女裝上對應(yīng)的尺碼分別是38,40,42,44,46,48 ②3.測量某地垂直地面方向上海拔500米以下的大氣溫度,得到從距離地面20米起每升高100米處的大氣溫度(單位℃)依次為25,24,23,22,21 ③
情景導(dǎo)學(xué)古語云:“勤學(xué)如春起之苗,不見其增,日有所長”如果對“春起之苗”每日用精密儀器度量,則每日的高度值按日期排在一起,可組成一個(gè)數(shù)列. 那么什么叫數(shù)列呢?二、問題探究1. 王芳從一歲到17歲,每年生日那天測量身高,將這些身高數(shù)據(jù)(單位:厘米)依次排成一列數(shù):75,87,96,103,110,116,120,128,138,145,153,158,160,162,163,165,168 ①記王芳第i歲的身高為 h_i ,那么h_1=75 , h_2=87, 〖"…" ,h〗_17=168.我們發(fā)現(xiàn)h_i中的i反映了身高按歲數(shù)從1到17的順序排列時(shí)的確定位置,即h_1=75 是排在第1位的數(shù),h_2=87是排在第2位的數(shù)〖"…" ,h〗_17 =168是排在第17位的數(shù),它們之間不能交換位置,所以①具有確定順序的一列數(shù)。2. 在兩河流域發(fā)掘的一塊泥板(編號K90,約生產(chǎn)于公元前7世紀(jì))上,有一列依次表示一個(gè)月中從第1天到第15天,每天月亮可見部分的數(shù):5,10,20,40,80,96,112,128,144,160,176,192,208,224,240. ②
1.判斷正誤(正確的打“√”,錯(cuò)誤的打“×”)(1)函數(shù)f (x)在區(qū)間(a,b)上都有f ′(x)<0,則函數(shù)f (x)在這個(gè)區(qū)間上單調(diào)遞減. ( )(2)函數(shù)在某一點(diǎn)的導(dǎo)數(shù)越大,函數(shù)在該點(diǎn)處的切線越“陡峭”. ( )(3)函數(shù)在某個(gè)區(qū)間上變化越快,函數(shù)在這個(gè)區(qū)間上導(dǎo)數(shù)的絕對值越大.( )(4)判斷函數(shù)單調(diào)性時(shí),在區(qū)間內(nèi)的個(gè)別點(diǎn)f ′(x)=0,不影響函數(shù)在此區(qū)間的單調(diào)性.( )[解析] (1)√ 函數(shù)f (x)在區(qū)間(a,b)上都有f ′(x)<0,所以函數(shù)f (x)在這個(gè)區(qū)間上單調(diào)遞減,故正確.(2)× 切線的“陡峭”程度與|f ′(x)|的大小有關(guān),故錯(cuò)誤.(3)√ 函數(shù)在某個(gè)區(qū)間上變化的快慢,和函數(shù)導(dǎo)數(shù)的絕對值大小一致.(4)√ 若f ′(x)≥0(≤0),則函數(shù)f (x)在區(qū)間內(nèi)單調(diào)遞增(減),故f ′(x)=0不影響函數(shù)單調(diào)性.[答案] (1)√ (2)× (3)√ (4)√例1. 利用導(dǎo)數(shù)判斷下列函數(shù)的單調(diào)性:(1)f(x)=x^3+3x; (2) f(x)=sinx-x,x∈(0,π); (3)f(x)=(x-1)/x解: (1) 因?yàn)閒(x)=x^3+3x, 所以f^' (x)=〖3x〗^2+3=3(x^2+1)>0所以f(x)=x^3+3x ,函數(shù)在R上單調(diào)遞增,如圖(1)所示