3)乘除运算①有理数的乘法法则:(老师给出,学生一起朗读)1. 两数相乘,同号得正,异号得负,并把绝对值相乘;2. 任何数与零相乘都得零;3. 几个不等于零的数相乘,积的符号由负因数的个数决定,当负因数有奇数个数,积为负;当负因数的个数为偶数个时,积为正;4. 几个有理数相乘,若其中有一个为零,积就为零。②有理数的除法法则:(老师提问,学生回答)1. 两个有理数相除,同号得正,异号得负,并把绝对值相除;2. 除以一个数等于乘以这个数的倒数。③关系(老师给出)除法转化为乘法进行运算。
一、课前准备师:同学们想一想,你同父母一起去商店买衣服时,衣服上的号码都有哪些,标志是什么?学生:我看到有些衣服上标有M、S、L、XL、XXL等号码.但我不清楚代表的具体范围,适合什么人穿,但肯定与身高、胖瘦有关.师:这位同学很善动脑,也爱观察.S代表最小号,身高在150~155cm的人适合穿S号.M号适合身高在155~160cm的人着装……厂家做衣服订尺寸也并不是按所有人的尺寸定做,而是按某个范围分组批量生产.你觉得这种生产方法有什么优点?学校要为同学们订制校服,为此小明调查了他们班50名同学的身高,结果(单位cm).如下
本节的内容主要是反比例函数的概念教学.反比例函数概念的建立,不能从形式上进行简单的抽象与概括,而是对这些实例从不同角度抽象出本质属性后,再进行概括。教材设计的基本思路是从现实生活中大量的反比例关系中抽象出反比例函数概念,让学生进一步感受函数是反映现实世界中变量关系的一种有效数学模型,逐步从对具体反比例函数的感性认识上升到对抽象的反比例函数概念的理性认识. 同时本节的学习内容,直接关系到本章后续内容的学习,也是继续学习其它各类函数的基础,其中蕴涵的类比、归纳、对应和函数的数学思想方法,对学生今后研究问题、解决问题以及终身的发展都是非常有益的.基于以上分析,本节教学设计是建立在一个个数学活动的基础上,经过对情境理解、本质抽象的积累而形成的.让学生对一类问题情境中两个变量间的关系,在充分经历写表达式,计算函数值和观察函数值随自变量变化规律的过程中,逐步概括形成反比例函数的概念.针对教学实际,我选取了贴学生现实的,有价值的实例“文具店里买学习用品”和“剪面积为定值的长方形纸片”等作为问题情境.
【类型二】 分式的约分约分:(1)-5a5bc325a3bc4;(2)x2-2xyx3-4x2y+4xy2.解析:先找分子、分母的公因式,然后根据分式的基本性质把公因式约去.解:(1)-5a5bc325a3bc4=5a3bc3(-a2)5a3bc3·5c=-a25c;(2)x2-2xyx3-4x2y+4xy2=x(x-2y)x(x-2y)2=1x-2y.方法总结:约分的步骤;(1)找公因式.当分子、分母是多项式时应先分解因式;(2)约去分子、分母的公因式.三、板书设计1.分式的基本性质:分式的分子与分母都乘以(或除以)同一个不为零的整式,分式的值不变.2.符号法则:分式的分子、分母及分式本身,任意改变其中两个符号,分式的值不变;若只改变其中一个符号或三个全变号,则分式的值变成原分式值的相反数.本节课的流程比较顺畅,先探究分式的基本性质,然后顺势探究分式变号法则.在每个活动中,都设计了具有启发性的问题,对各个知识点进行分析、归纳总结、例题示范、方法指导和变式练习.一步一步的来完成既定目标.整个学习过程轻松、愉快、和谐、高效.
授课 日期 班级16高造价 课题: §10.1 计数原理 教学目的要求: 1.掌握分类计数原理与分步计数原理的概念和区别; 2.能利用两个原理分析和解决一些简单的应用问题; 3.通过对一些应用问题的分析,培养自己的归纳概括和逻辑判断能力. 教学重点、难点: 两个原理的概念与区别 授课方法: 任务驱动法 小组合作学习法 教学参考及教具(含多媒体教学设备): 《单招教学大纲》、课件 授课执行情况及分析: 板书设计或授课提纲 §10.1 计数原理 1、加法原理 2、乘法原理 3、两个原理的区别
1、方程的定义1)像这种用等号“=”来表示相等关系的式子,叫等式。(老师给出定义。)2)请大家观察左边的这些式子,看看它们有什么共同的特征?(老师提出问题。)3)列方程时,要先设字母表示未知数,然后根据问题中的相等关系,写出含有未知数的等式叫做方程。(学生思考后,老师给出新学内容方程的定义。)4)判断方程的两个关键要素: ①有未知数 ②是等式(老师提问,并给出。)
课程分析中专数学课程教学是专业建设与专业课程体系改革的一部分,应与专业课教学融为一体,立足于为专业课服务,解决实际生活中常见问题,结合中专学生的实际,强调数学的应用性,以满足学生在今后的工作岗位上的实际应用为主,这也体现了新课标中突出应用性的理念。分段函数的实际应用在本课程中的地位:(1) 函数是中专数学学习的重点和难点,函数的思想贯穿于整个中专数学之中,分段函数在科技和生活的各个领域有着十分广泛的应用。(2) 本节所探讨学习分段函数在生活生产中的实际问题上应用,培养学生分析与解决问题的能力,养成正确的数学化理性思维的同时,形成一种意识,即数学“源于生活、寓于生活、用于生活”。教材分析 教材使用的是中等职业教育课程改革国家规划教材,依照13级教学计划,函数的实际应用举例内容安排在第三章函数的最后一部分讲解。本节内容是在学生熟知函数的概念,表示方法和对函数性质有一定了解的基础上研究分段函数,同时深化学生对函数概念的理解和认识,也为接下来学习指数函数和对数函数作了良好铺垫。根据13级学生实际情况,由生活生产中的实际问题入手,求得分段函数此部分知识以学生生活常识为背景,可以引导学生分析得出。
课题序号 授课班级 授课课时2授课形式 教学方法 授课章节 名称9.5柱、锥、球及其组合体使用教具 教学目的1、使学生认识柱、锥、球及其组合体的结构特征,并能运用这些特征描述生活中简单物体的结构。 2、让学生了解柱、锥、球的侧面积和体积的计算公式。 3、培养学生观察能力、计算能力。
课程课题随机事件和概率授课教师李丹丹学时数2授课班级 授课时间 教学地点 背景分析正确使用两个基本原理的前提是要学生清楚两个基本原理使用的条件;分类用加法原理,分步用乘法原理,单纯这点学生是容易理解的,问题在于怎样合理地进行分类和分步教学中给出的练习均在课本例题的基础上稍加改动过的,目的就在于帮助学生对这一知识的理解与应用 学习目标 设 定知识目标能力(技能)目标态度与情感目标1、理解随机试验、随机事件、必然事件、不可能事件等概念 2、理解基本事件空间、基本事件的概念,会用集合表示基本事件空间和事件 1 会用随机试验、随机事件、必然事件、不可能事件等概念 2 会用基本事件空间、基本事件的概念,会用集合表示基本事件空间和事件 3、掌握事件的基本关系与运算 了解学习本章的意义,激发学生的兴趣. 学习任务 描 述 任务一,随机试验、随机事件、必然事件、不可能事件等概念 任务二,理解基本事件空间、基本事件的概念,会用集合表示基本事件空间和事件
课程名称数学课题名称8.2 直线的方程课时2授课日期2016.3任课教师刘娜目标群体14级五高班教学环境教室学习目标知识目标: (1)理解直线的倾角、斜率的概念; (2)掌握直线的倾角、斜率的计算方法. 职业通用能力目标: 正确分析问题的能力 制造业通用能力目标: 正确分析问题的能力学习重点直线的斜率公式的应用.学习难点直线的斜率概念和公式的理解.教法、学法讲授、分析、讨论、引导、提问教学媒体黑板、粉笔
一、定义: ,这一公式表示的定理叫做二项式定理,其中公式右边的多项式叫做的二项展开式;上述二项展开式中各项的系数 叫做二项式系数,第项叫做二项展开式的通项,用表示;叫做二项展开式的通项公式.二、二项展开式的特点与功能1. 二项展开式的特点项数:二项展开式共(二项式的指数+1)项;指数:二项展开式各项的第一字母依次降幂(其幂指数等于相应二项式系数的下标与上标的差),第二字母依次升幂(其幂指数等于二项式系数的上标),并且每一项中两个字母的系数之和均等于二项式的指数;系数:各项的二项式系数下标等于二项式指数;上标等于该项的项数减去1(或等于第二字母的幂指数;2. 二项展开式的功能注意到二项展开式的各项均含有不同的组合数,若赋予a,b不同的取值,则二项式展开式演变成一个组合恒等式.因此,揭示二项式定理的恒等式为组合恒等式的“母函数”,它是解决组合多项式问题的原始依据.又注意到在的二项展开式中,若将各项中组合数以外的因子视为这一组合数的系数,则易见展开式中各组合数的系数依次成等比数列.因此,解决组合数的系数依次成等比数列的求值或证明问题,二项式公式也是不可或缺的理论依据.
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.
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. 以上黑体部分在句中作表语。2. 句1、2、3中的that在从句中不作成分,只起连接作用。 Step2: Review the basic components of predicative clauses1.Definition
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
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
The newspaper reported more than 100 people had been killed in the thunderstorm.报纸报道说有一百多人在暴风雨中丧生。(2)before、when、by the time、until、after、once等引导的时间状语从句的谓语是一般过去时,以及by、before后面接过去的时间时,主句动作发生在从句的动作或过去的时间之前且表示被动时,要用过去完成时的被动语态。By the time my brother was 10, he had been sent to Italy.我弟弟10岁前就已经被送到意大利了。Tons of rice had been produced by the end of last month. 到上月底已生产了好几吨大米。(3) It was the first/second/last ... time that ...句中that引导的定语从句中,主语与谓语构成被动关系时,要用过去完成时的被动语态。It was the first time that I had seen the night fact to face in one and a half years. 这是我一年半以来第一次亲眼目睹夜晚的景色。(4)在虚拟语气中,条件句表示与过去事实相反,且主语与谓语构成被动关系时,要用过去完成时的被动语态。If I had been instructed by him earlier, I would have finished the task.如果我早一点得到他的指示,我早就完成这项任务了。If I had hurried, I wouldn't have missed the train.如果我快点的话,我就不会误了火车。If you had been at the party, you would have met him. 如果你去了晚会,你就会见到他的。
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.
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!
You have no excuse for not going.你没有理由不去。He was punished for not having finished his homework.他因未完成作业而受到惩罚。2.动词ing形式复合结构由物主代词或人称代词宾格、名词所有格或普通格加动词ing,即“sb./sb.'s+doing”构成。动词ing形式的复合结构实际上是给动词ing形式加了一个逻辑主语。动词ing形式的复合结构有四种形式:①形容词性物主代词+动词ing②名词所有格+动词ing③代词宾格+动词ing④名词+动词ingHer coming to help encouraged all of us.她来帮忙鼓舞了我们所有人。The baby was made awake by the door suddenly shutting.这个婴儿被突然的关门声吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做饭的样子吗?无生命名词无论是作主语还是作宾语都不能用第②种形式。Tom's winning first prize last year impressed me a lot.汤姆去年得了一等奖使我印象深刻。Do you mind my/me/Jack's/Jack leaving now?你介意我/杰克现在离开吗?Excuse me for my not coming on time.很抱歉我没能按时来。His father's being ill made him worried.他父亲病了,他很担心。We are looking forward to the singer's/the singer to give us a concert.我们盼望着这位歌手来给我们举办一场演唱会。
1、问题1的设计基于学生已有的一元一次方程的知识,学生独立思考问题,同学会考虑到题中涉及到等量关系,从中抽象出一元一次方程模型;同学可能想不到用方程的方法解决,可以由组长带领进行讨论探究.2、问题2的设计为了引出二元一次方程,但由于同学的知识有限,可能有个别同学会设两个未知数,列出二元一次方程;如果没有生列二元一次方程,教师可引导学生分析题目中有两个未知量,我们可设两个未知数列方程,再次从中抽象出方程模型.根据方程特点让生给方程起名,提高学生学习兴趣.3、定义的归纳,先请同学们观察所列的方程,找出它们的共同点,并用自己的语言描述,组内交流看法;如果学生概括的不完善,请其他同学补充. 交流完善给出定义,教师规范定义.