第一篇：江蘇省常州市西夏墅中學高中英語 Unit2 Language Reading教學設(shè)計2 牛津譯林版必修3（寫寫幫推薦）

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元：Unit 2 Language

板

塊：Reading

課堂設(shè)計指導思想：

本課時為Reading理解過后的第二課時，著重于語言知識的講授，即我們常說的語言點課。語言點的講解容易陷入枯燥的泥淖，要上得生動需要藝術(shù)。而且，語言點的講解宜精不宜多，宜多練優(yōu)于多講，因為了一旦內(nèi)容過多，學生就會生吞活剝、囫圇吞棗無法消化；如果講得過多，學生沒有機會操練、體會、鞏固，就不可能真正地理解掌握；因此，不如精選精練，扎扎實實。本著這樣的設(shè)想，本節(jié)課的設(shè)計為語言點課安排了一個課時，選擇了課文中出現(xiàn)的十二個語言點，逐一講解，在句子層面進行多方位練習，并在此基礎(chǔ)上要求學生在課后將所學知識運用到語篇的寫作中。Teaching aims: 1.Do some revision of what have been learned in the last lesson.2.Acquire the usage of the language items in the text.3.Apply the language items into practical use.Teaching procedures: Step 1 Revision The teacher starts the lesson with a short revision of what have been learned in the previous lessons.This part consists of two activities—to match the words and their definitions and to fill in the blanks.【設(shè)計說明】在課的一開始，設(shè)計了復習環(huán)節(jié)，優(yōu)勢有二：第一，幫助教師檢查學生對之前學習內(nèi)容的掌握，有利于教師及時了解教學對象的學習情況，了解教學的效果，在必要情況下，及時調(diào)整教學內(nèi)容和進度，從而更好地為教學對象服務(wù)，以實現(xiàn)教學效果的提高；第二，傳遞有效學習策略的相關(guān)信息：復習是學習過程的一個重要環(huán)節(jié)，教師如果能常常有意設(shè)計復習活動，提高學生及時復習的意識，培養(yǎng)他們良好的學習習慣，這將會讓學生終身受益。

Step 2 Presentation Present all the language items that should be coved in the following lesson.Ask the students to find them out in the text.【設(shè)計說明】語言點的學習，要避免一味灌輸。在講述語言點時，首先應該讓學生明確學習目標，因此，在此處，教師將精選的詞匯率先呈現(xiàn)給學生，使學生的學習有計劃、有目的。Step 3 Discussion of the language items 1.be made up of make up 化妝，編造，彌補 be made up of … 由……構(gòu)成 be made of … 由……制造 be made from...由……制造

She quickly made herself up and went out for the party.Don’t believe him.He made the whole story up.I must make up the lost time by extra work.1.My favorite salad is made of lettuce, tomatoes and cucumber.2.She made up a story to comfort her little daughter.3.Nylon is made from air, coal and water.4.The audience is made up of very young children.5.The toy cost a dollar and Ted only had fifty cents, so Father made up the difference.6.Society is made up of people with widely differing abilities.2.consist 1)組成，構(gòu)成 +of: A university consists of teachers, administrators and students.大學由教師,行政人員和學生組成。Our book consists of 3 units.我們的書有3單元。2)主要是，主要在于 +in Happiness consists in appreciating what you have.快樂就在于滿足所擁有的。3.contribute to 1)to help to lead to the result導致;Drink contributed to his death.酒造成了他的死亡。

2)捐(款);捐獻,捐助(donate to)他將積蓄的一半捐獻給紅十字會。

He contributed half of his savings to the Red Cross.3)投(稿)[(+to)] 他給雜志投稿他的詩。

He contributed his poems to the magazine.3.control 1)V.控制；支配；管理；克制；抑制

She is skillful enough to control the machine.她已有了足夠的技術(shù)可以操縱這臺機器了。

The British government at that time controlled the island.當時英國政府控制該島。

You must learn to control your temper.你必須學會克制著不發(fā)脾氣。2)n.支配；控制；調(diào)節(jié)；抑制 [(+of/over)] They have no control over him.他們控制不了他。

There must be someone who can take control of these naughty children.應該有人能管住這些淘氣的孩子。Some more phrases: in control of … in the control of … be/ come/ bring/get under control under the control of … be/get out of control lose control of … The boy is no longer _in/under the control of_ his parents.Police at present lost control of the crowd.They asked for help.With the help of firefighters, they got the fire _under control_.Mum was angry to see her children out of control.Who do you let be in control of_ your class while you’re out? 4.replace vt.1)取代；以……代替 [(+with/by)] The brakes have to be replaced.剎車需要更換。

Electric lights have replaced candles.電燈已經(jīng)取代了蠟燭。2)把...放回(原處)She replaced the receiver.她將聽筒放了回去。3)歸還;償還

I will replace the cup I broke.我愿用一個新杯子賠還我打碎的一只。5.result in V.1)結(jié)果;導致(lead to)Carelessness resulted in lots of accidents.粗心造成大量交通事故。

2)result from(because of, due to)His failure resulted largely from his laziness.他的失敗主要是懶惰所致。His success C working hard.Too much cigarettes A hisdeaths.He had to take a taxi to work B the bad weather.A.result in B.as a result of C.results from D.as a result 6.raise vt./ n 1)The baby was raised on soybean milk.這孩子是用豆?jié){喂養(yǎng)大的。

2)The landlord raised my rent to $200.房東把租金提高到$ 200。3)They are going to raise money for the school buildings.他們將為蓋校舍籌集資金。

4)He raised his glass and said: “Your health, Carl.” 他舉起了杯子說道:“祝你健康,卡爾?！?5)None of them raised any objection.他們誰也沒提出反對意見。True or false: 1.Prices have been risen up.F raised 2.The sun raises in the east and sets in the west.F rises 3.Jack was raised by his aunt after his parents passed away.T 【設(shè)計說明】逐一講解語言點，通過中英互譯、完成句子、改錯、單選等多種形式進行操練，增進學生對這些語言點的理解掌握。

Step 5 Homework Make up a story using the expressions we have learned today.【設(shè)計說明】課間的講解、操練仍然停留在句的層面，運用所學表達至語篇雖是較高的要求，也是合理的要求。語言本身的存在就是在一定的Discourse中的，因此，語言點的教學也不應該割裂與語篇的自然聯(lián)系。

第二篇：江蘇省常州市西夏墅中學高中英語 Unit1 Advertising Reading教學設(shè)計2 牛津譯林版必修4

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元：Unit 1 Advertising

板

塊：Reading 2 課堂設(shè)計指導思想：

本堂課是閱讀課的第二課時。本課旨在鞏固學生從文章中獲取的主要信息和對語篇的整體理解。在此基礎(chǔ)上，操練文章中的主要語言點。形式多樣的語言點操練過程既是學生學習語言知識的過程，更是訓練學生聽說讀寫技能的過程。本課語言點操練的重點是習慣用語和固定搭配，主要以聽說的方式，在句子層面讓學生當堂操練語言點，為綜合運用英語打下基礎(chǔ)。

Teaching aims: 1.To get to grasp the usage of the main language items.2.To train listening, speaking, reading and writing skills by practicing the language items.Teaching procedures: Step 1 Revision Ask students to fill in the blanks with the first letters given.The short passage is a summary of the reading text which is closely related to advertisements.【設(shè)計說明】讓學生根據(jù)所給首字母填空完成短文，可復習鞏固上一課時對文章的理解，并自然導入本課。

Step 2 Language focus List the main language items in the reading text and draw students’ attention to them.【設(shè)計說明】列出主要語言點，讓學生清楚了解本堂語言操練課的重點所在。Step 3 Explanation and practice Explain the main usage of the listed language items and use different ways, such as sentence translation, multiple choices to help students to practice.【設(shè)計說明】精講所列出的主要語言點，通過句子翻譯，選擇填空等方式幫助學生操練這些語言點，以達到逐步掌握其用法，并靈活運用的目的。Step 4 Consolidation 1 Let students choose the right words and expressions to fill in the blanks with their proper forms.【設(shè)計說明】這一練習形式可幫助學生在一定的語境中鞏固記憶文章中的短語和習慣用法，并有助于培養(yǎng)語感，有助于寫作能力的提高。Step 5 Consolidation 2

Ask students to search their memory for the words and expressions learnt in this section and complete the sentences.【設(shè)計說明】再次鞏固語言要點，為綜合運用鋪設(shè)道路。Step 6 Homework Let students finish A1 and A2 on Page 90, and write a short passage with the phrases we learnt in this lesson.【設(shè)計說明】通過書后練習進一步鞏固本課語言要點。書面表達練習要求學生靈活運用所學語言點，有利于提高他們的寫作能力和綜合運用能力。

第三篇：江蘇省常州市西夏墅中學高中數(shù)學 數(shù)列專題復習2 數(shù)列中的數(shù)學思想教學設(shè)計 蘇教版必修5

數(shù)列專題復習2——數(shù)列中的數(shù)學思想

教學目標：

1．知識與技能：

能夠靈活運用方程思想、化歸與轉(zhuǎn)化思想、函數(shù)思想對數(shù)列問題進行求解． 2．過程與方法：

使學生在已掌握的數(shù)列題型求解方法上進一步提高解題水平，明確數(shù)列與數(shù)學思想的內(nèi)在聯(lián)系．

教學重點：

掌握數(shù)列題型中數(shù)學思想方法的應用； 教學難點：

掌握數(shù)列題型中數(shù)學思想方法的應用．

教學方法：

講練結(jié)合、自主探究．

教學過程：

一、問題情境

問題1．我們以前的學習中接觸過哪些數(shù)學思想方法？ 問題2．前一段的數(shù)列學習中運用了哪些數(shù)學思想方法？

二、學生活動

1．數(shù)列中有方程思想、化歸與轉(zhuǎn)化思想、函數(shù)與數(shù)形結(jié)合思想． 2．討論并從習題中找出具體的題目中分別體現(xiàn)哪些思想方法．

三、建構(gòu)數(shù)學

引導學生自己總結(jié)出數(shù)學中幾種思想方法．

（一）數(shù)列中的方程思想：

等差數(shù)列有兩個基本量a1,d，等比數(shù)列有兩個基本量a1,q，等差與等比數(shù)列的兩個基本問題an,Sn都可以用兩個基本量來表示，所以列出關(guān)于兩個關(guān)于基 本量的方程組來求解，這種方法又可稱為基本量法．

（二）數(shù)列中的化歸與轉(zhuǎn)化思想：

我們在處理數(shù)學問題時，常常將待解決的問題通過轉(zhuǎn)化，化歸成為一類我們比較熟悉問題來解決．

（三）數(shù)列中的函數(shù)與數(shù)形結(jié)合思想：

數(shù)列是一種特殊的函數(shù)，數(shù)列的通項公式和前n項和公式都可以看成n的函數(shù)，特別是等差數(shù)列的通項公式可以看成是n的一次函數(shù)，而其求和公式可以看成是常數(shù)項為零的二次函數(shù)，因此許多數(shù)列問題可以用函數(shù)的思想進行分析，加以解決．

四、數(shù)學運用

例1 在等比數(shù)列?an?中，如果a1?a2?40，a3?a4?60，那么a7?a8?.分析 以等比數(shù)列的首項a1和公比q為基本量列方程組求解，適當運用整體思想可使運算簡化.解 ??a1?a1q?40，32，?q?232?a1q?a1q?60．3a7?a8?a1q6?a1q7?a1q6(1?q)?40?()3?135．

2變式 已知等比數(shù)列?an?中前8項的和S8?30，前16項的和S16?150，求S20.解 設(shè)?an?的公比為q，當q?1時，S8?8a1?30?a1?15，4S16?16a1?150?a1?75，故q?1.8?a1?1?q8???30?1?1?q? ??16?a1?1?q??150 ?2??1?q??1?得1?q8?5，?2??q8?4． 帶入（1）式可得?q4?2．a(chǎn)1??10，1?q 2 ?S20a11?q20a11?q4??1?q1?q???????310.5點評 解題過程中應注意對等比數(shù)列中q?1這種特殊情況的討論.另外本題的求解需要有整體思想，即必須把

a11?q當成一個整體來解.例2 已知數(shù)列?an?滿足an?1?2an?1，且a1?1，（1）證明數(shù)列?an?1?是等比數(shù)列；（2）求數(shù)列?an?的通項公式.解（1）令bn?an?1，故只需證?bn?是等比數(shù)列，bn?1b?an?1?12an?1?12?an?1?a?1?a?2，b1?a1?1?2，nn?1an?n?1?數(shù)列?bn?是以2為首項，2為公比的等比數(shù)列.即數(shù)列?an?1?是以2為首項，2為公比的等比數(shù)列.（2）bn?2?2n?1?2n，即an?1?2n，∴an?2n?1.變式 已知數(shù)列?an?的前n項和滿足Sn??an?n，且a1?12，（1）證明數(shù)列?an?1?是等比數(shù)列；（2）求數(shù)列?an?的前n項和Sn.解 S1n?1?Sn??an?1?n?1???an?n??an?1?2a1n?2 令bn?an?1，故只需證?bn?是等比數(shù)列，?1?bn?1b?a?1an???11a111?1na1??22?a?2n?2?an??2n?1??1，b?11?a1?1?n?n?1an?1an?122，∴數(shù)列?b1n?是以?2為首項，12為公比的等比數(shù)列.即數(shù)列?a11n?1?是以?2為首項，2為公比的等比數(shù)列.3

1?1?（2）bn?????2?2?n?11?1??1?????，即an?1???? ∴an?1?n.2?2??2?nnSn?a1?a2?a3???an1??1?1??1?????1????1?2???1?3?????1?n?

2222????????n1??1????1????2?1?1??2????111?n???2?3???n??n??n?1?n．12?2?2221?2例3 已知數(shù)列?an?是等差數(shù)列，數(shù)列?bn?是等比數(shù)列，其公比q?1，且bi?0y（i?1,2,3,?），若a1?b1，a11?b11,則a6與b6的大小關(guān)系為.分析（方法一）q?1?b1?b11，bi?0，所以a?a11b1?b11a6?1??b1b11?b62?b622．

（方法二）等差數(shù)列是定義在正整數(shù)集上的一次函數(shù)，等比數(shù)列（q?1）時是定義在正整數(shù)集上的指數(shù)函數(shù)．由a1?b1，a11?b11知

Ｏ

x

兩函數(shù)有兩個交點如圖，顯然a6?b6，而且當1?n?11,n?N時都有an?bn，當n?11時，an?bn.五、要點歸納與方法小結(jié)

1.數(shù)列中的方程思想：基本量法是通法，要注意運算技巧.2.數(shù)列中的化學與轉(zhuǎn)化思想：將非等差等比問題轉(zhuǎn)化為等差等比數(shù)列問題求解是突破點.3.數(shù)列中的函數(shù)與數(shù)形結(jié)合思想：構(gòu)造函數(shù)，用圖象輔助，能起到出奇制勝的效果.4

第四篇：2016學年江蘇省常州市西夏墅中學高二英語教案：unit1《 the written word 》reading 2(牛津版選修8)

牛津高中英語教學設(shè)計

單

元：Unit 1 The written word 板

塊：Reading 2

Thoughts on the design: 本教學方案分為四個部分，分別為revision、language points、consolidation與homework。

在“revision”環(huán)節(jié)，教師將要求學生復述上節(jié)課所學課文作為本課的開端，旨在一方面提高口語，激發(fā)其學習興趣；另一方面通過回顧上節(jié)課的內(nèi)容形成自然過渡，起到承上啟下的作用，為講新知識打下一個基礎(chǔ)。在“l(fā)anguage points”環(huán)節(jié)，教師將以兩步走的方式開展教學，其中滲透著PPT教學模式。第一步根據(jù)Krashen輸入假設(shè)理論的i+1原理，教師將引導學生利用已學知識進行新語言點的習得，即“practice to present”；第二步，教師將引導學生根據(jù)第一步所學進行相關(guān)練習，即“practice”。在完成學習的基礎(chǔ)上，學生將在“consolidation”環(huán)節(jié)對所學知識點進行總結(jié)性練習，以達到鞏固的目的。

Teaching aims: 1.Encourage the students to raise reading ability by focusing on language points;2.Get the students to grasp the new language usage in the text by learning them.Procedures: Step 1 Revision 1.Think of a possible ending for the novel.2.Retell the story of Great Expectations.Step 2 Language points and use 1.Key words: Explanation(通過填詞的方式把關(guān)鍵詞挑出來講解和操練，見PPT 6-11。)Fill in the blanks first and then practise the uses of the key words.What is c_____ literature? C_______ are the a______ of the l_______ world, which 1

are still well received today.They are e_______ of great writing and wisdom.Many a__________ films are based on the classics.For example, in 1998, a modern a__________ of Charles Dickens’ novel Great Expectations, one of his best-known works, was released in cinemas.Great Expectations is s____ in England in the early 1800s.The main character in the novel is Pip.He lives with his mean sister and her kind and simple husband, Joe.It is a m_____ night when the story begins.Mist is a s_____ of danger which adds interest, t______ and deeper meaning to the text.Later in the story, Pip receives a large sum of money from a generous stranger, which is a twist in the p______.He uses the f________ to move to London.He settled there so he can become an e_______ gentleman, but he gradually develops the shortcomings of being shallow and being prejudiced against his old companions, because he has rigid ideas of what it means to be c_____ and to be a gentleman.What it means to be a gentleman is an important t_____ in Great Expectations.By the end of the story, Pip learns that w________ doesn’t buy happiness and that friends are more important than a fancy education.Practice: Fill in the following blanks using the given words.1.He likes _______ novels and Jane Austen’s novels are among the best-loved ________ in English literature.(classic)2.Though she is interested in ______, she is not a _______ writer.(literary)3.Michael _______ to the new job very well, which was beyond our expectations.The plot had to be changed a little bit since the film is an __________ of the book.(adapt)4.The girl and her best friend were both very ________ and nervous about the results of the examination.The argument over the game created ________ between the two of them.(tense)

2.Key phrases: Explanation(先翻譯關(guān)鍵詞組，再把重難點挑出來練，以此達到掌握的目的，見PPT 13-16。)

1.由??改編 2.在世界占一席之地 3.在架子上塵封 4.被改編成電影 5.每一次 6.肥皂劇 7.古典文學 8.出版

9.一心想要做?? 10.華而不實的教育

Comparison: at times/at one time/at a time/in time/in no time/at no time 1.We were ____________ for the train.2.__________ Chinese were regarded as Asian patients, but now we are strong enough to hold the Olympics.3.____________ will Chinese people bow(低頭)to huge difficulties even though we have suffered a lot.3.Key sentences: Explanation(把重點句和結(jié)構(gòu)挑出來講解再進行練習，以此達到掌握句型的目的，見PPT 18-25。)1.His tomb reads, ‘By his death, one of England’s greatest writers is lost to the world.’

2.Pip’s sister seldom has a kind word to say, but Joe is a kind and simple man, who would rather die than see any harm come to Pip.3.He has rigid ideas of what it means to be civil and to be a gentleman, and is embarrassed by Joe because he does not fit these.Key sentence structures: 1.Why else would many films based on them be successful? 2.Pip dislikes it when Joe comes to visit him in London.Step 3 Consolidation：

Explanation(鞏固部分再一次通過填詞、詞組和翻譯的方式復習重點內(nèi)容。見PPT 27-29)

Fill in the blanks using the following phrases:(be lost to/be bent on/gather dust on the shelf/ come out /be adapted from)1.My guitar has just been _______________________ since I injured my hand.2.Many films ________________ classic works.3.A lot of new books _________ every day 4.By the death of Ba Jin, one of China’s greatest writers ____________ the world.5.He _________ winning at all costs.根據(jù)首字母提示完成下列句子：

1.Many people were g_______ enough to donate enough money to the people in the disaster regions.2.The play is an a_________ of a short novel.3.Ann’s uncle died suddenly, leaving all his f______ to her.4.He was v_____ about his looks, spending hours in the gym.5.Prisoners reported being regularly a______ by their guards.6.Keep a c_________ tongue in your head!Don’t speak rudely.7.The _____(曲折)in the plot is always the attraction to literature lovers.8.Parts of this school are in d__________ need of repair.Translation: 1.作為一位母親，她寧愿自己挨餓也不愿孩子受到任何的傷害。(would rather ? than ?/ come to)2.你這樣說真有禮貌。(civil)

Step 4 Homework: 1.Memorize the words, phrases and sentences we learned today.2.Make up a short story using the given adjectives.

第五篇：江蘇省常州市西夏墅中學高中數(shù)學 2.3.1等比數(shù)列的概念教學設(shè)計 蘇教必修5

2.3.1 等比數(shù)列的概念

教學目標：

1.體會等比數(shù)列是用來刻畫一類離散現(xiàn)象的重要數(shù)學模型，理解等比數(shù)列的概念． 2.利用等比數(shù)列解決實際問題． 教學重點：

等比數(shù)列的概念． 教學難點：

理解等比數(shù)列“等比”的特點．可以通過與等差數(shù)列進行類比來突破難點．

教學方法：

啟發(fā)式、討論式． 教學過程：

一、問題情境

情境1：某種細胞，如果每個細胞每分鐘分裂為2個，那么每過1分鐘，1個細胞分裂的個數(shù)依次為

1,2,4,8,16，情境2：“一尺之棰，日取其半，萬世不竭”的意思為：一尺長的木棒，每日取其一半，永遠也取不完．如果將“一尺之棰”視為1份，那么每日剩下的部分依次為

1111，，24816

情境3：某轎車的售價約為36萬元，年折舊率約為10﹪（就是說這輛車每年減少它的價值的10﹪），那么該車從購買當年算起，逐年的價值依次為 36,36?0.9,36?0.9,36?0.9,問題：與等差數(shù)列相比，上面這些數(shù)列有什么特點？

二、學生活動 通過觀察，發(fā)現(xiàn)：

1．上述數(shù)列的共同特征，從第2項起，每一項都與它的前一項的比等于同一個常數(shù)．而等差數(shù)列的特征是，從第2項起，每一項都與它的前一項的差等于同一個常數(shù)．

2．根據(jù)這一規(guī)律可以發(fā)現(xiàn)任何一項都可以找出來．

通過討論，得到這些問題共同的特點是，每一項與它的前一項的比都等于同一個常數(shù)．

三、建構(gòu)教學

1.歸納總結(jié)，形成等比數(shù)列的概念：

一般地，如果一個數(shù)列從第2項起，每一項與它的前一項的比都等于同一個常數(shù)，那么這個數(shù)列就叫做等比數(shù)列，這個常數(shù)叫做等比數(shù)列的公比，公比通常用字母q表示．

2.符號記法，若數(shù)列?an?為等比數(shù)列，公比為q，則

an?q(n?2)． an?1問題1：下列數(shù)列是否為等比數(shù)列，如果是，公比是多少？（1）1,1,1,1,1；（2）0,1,2,4,8；（3）1,?1111234，?,；（4）x,x,x,x． 24816問題2：一個數(shù)列是等比數(shù)列，那么它的項和公比必須滿足什么條件？ 問題3：當?shù)缺葦?shù)列的公比為負數(shù)的時候，數(shù)列每一項有什么樣的特征？（學生討論回答）

答 問題1中（1）、（3）是等比數(shù)列，公比分別是1和?等于0的時候是，等于0的時候不是．

問題2中等比數(shù)列的每一項都不能為0，公比也不能等于0． 問題3中項是呈正負交替出現(xiàn)，形成搖擺數(shù)列． 3.等比中項的概念．

若a,G,b成等比數(shù)列，那么G叫a和b的等比中項，且G2?ab,G??ab． 注：同號的兩個數(shù)才有等比中項，等比中項有兩個，它們互為相反數(shù)．

四、數(shù)學運用 1.例題．

例2（1）在等比數(shù)列?an?中，是否有an?an?1an?1(n?2)？

21；（2）不是；（4）當x不2（2）如果數(shù)列?an?中，對于任意的正整數(shù)?n?2?，都有an?an?1an?1，那

2么?an?一定成等比數(shù)列嗎？

引導學生利用課本P36例3的證明過程對等比數(shù)列進行討論，只是要提醒學生等比數(shù)列 2 每一項均不為0．所以（2）不一定成立，只有在每一項均不為0的時候才成立．

總結(jié)判定數(shù)列是否是等比數(shù)列的兩個方法：定義法和等比中項法． 例3 已知等比數(shù)列?an?的首項為a1，公比為q．

（1）新數(shù)列an,an?1,an?2,?,a2,a1也是等比數(shù)列嗎？如果是，公比是多少？（2）依次取出數(shù)列?an?所有的奇數(shù)項，組成一個新數(shù)列，這個數(shù)列還是等 比數(shù)列嗎？如果是，它的首項和公比是多少？

（3）數(shù)列?can??c?0?是等比數(shù)列嗎？如果是，它的首項和公比是多少？ 引導學生討論，按照等比數(shù)列的定義，利用

an?q(n?2)判斷．歸納總結(jié)一般性的結(jié)論：an?1如果取出的項下標成等差數(shù)列，按照原來的順序排列形成的新數(shù)列依然是等比數(shù)列，公比是qd（d為下標成等差數(shù)列時的公差）

2.練習．

（1）已知下列數(shù)列是等比數(shù)列，請在括號內(nèi)填上適當?shù)臄?shù)：

①（），3,27； ②3，（），5； ③1，（），（），81． 8_．（2）直角三角形的三邊a,b,c成等比，c為斜邊，則sinA?__________（3）已知數(shù)列?an?滿足：lgan?3n?5，試用定義證明?an?是等比數(shù)列．

五、要點歸納與方法小結(jié)

1.了解等比數(shù)列的概念，形成與等差數(shù)列的一個對比； 2.對于等比數(shù)列的每一項均不為0要進行討論； 3.證明一個數(shù)列是等比數(shù)列要用定義法證明，即

六、課外作業(yè)

課本練習P51第1，2，3，6題．

an?q?n?2?． an?1 3