一、情境导学我国著名数学家吴文俊先生在《数学教育现代化问题》中指出:“数学研究数量关系与空间形式,简单讲就是形与数,欧几里得几何体系的特点是排除了数量关系,对于研究空间形式,你要真正的‘腾飞’,不通过数量关系,我想不出有什么好的办法…….”吴文俊先生明确地指出中学几何的“腾飞”是“数量化”,也就是坐标系的引入,使得几何问题“代数化”,为了使得空间几何“代数化”,我们引入了坐标及其运算.二、探究新知一、空间直角坐标系与坐标表示1.空间直角坐标系在空间选定一点O和一个单位正交基底{i,j,k},以点O为原点,分别以i,j,k的方向为正方向、以它们的长为单位长度建立三条数轴:x轴、y轴、z轴,它们都叫做坐标轴.这时我们就建立了一个空间直角坐标系Oxyz,O叫做原点,i,j,k都叫做坐标向量,通过每两个坐标轴的平面叫做坐标平面,分别称为Oxy平面,Oyz平面,Ozx平面.
问题导学类比椭圆几何性质的研究,你认为应该研究双曲线x^2/a^2 -y^2/b^2 =1 (a>0,b>0),的哪些几何性质,如何研究这些性质1、范围利用双曲线的方程求出它的范围,由方程x^2/a^2 -y^2/b^2 =1可得x^2/a^2 =1+y^2/b^2 ≥1 于是,双曲线上点的坐标( x , y )都适合不等式,x^2/a^2 ≥1,y∈R所以x≥a 或x≤-a; y∈R2、对称性 x^2/a^2 -y^2/b^2 =1 (a>0,b>0),关于x轴、y轴和原点都是对称。x轴、y轴是双曲线的对称轴,原点是对称中心,又叫做双曲线的中心。3、顶点(1)双曲线与对称轴的交点,叫做双曲线的顶点 .顶点是A_1 (-a,0)、A_2 (a,0),只有两个。(2)如图,线段A_1 A_2 叫做双曲线的实轴,它的长为2a,a叫做实半轴长;线段B_1 B_2 叫做双曲线的虚轴,它的长为2b,b叫做双曲线的虚半轴长。(3)实轴与虚轴等长的双曲线叫等轴双曲线4、渐近线(1)双曲线x^2/a^2 -y^2/b^2 =1 (a>0,b>0),的渐近线方程为:y=±b/a x(2)利用渐近线可以较准确的画出双曲线的草图
问题导学类比用方程研究椭圆双曲线几何性质的过程与方法,y2 = 2px (p>0)你认为应研究抛物线的哪些几何性质,如何研究这些性质?1. 范围抛物线 y2 = 2px (p>0) 在 y 轴的右侧,开口向右,这条抛物线上的任意一点M 的坐标 (x, y) 的横坐标满足不等式 x ≥ 0;当x 的值增大时,|y| 也增大,这说明抛物线向右上方和右下方无限延伸.抛物线是无界曲线.2. 对称性观察图象,不难发现,抛物线 y2 = 2px (p>0)关于 x 轴对称,我们把抛物线的对称轴叫做抛物线的轴.抛物线只有一条对称轴. 3. 顶点抛物线和它轴的交点叫做抛物线的顶点.抛物线的顶点坐标是坐标原点 (0, 0) .4. 离心率抛物线上的点M 到焦点的距离和它到准线的距离的比,叫做抛物线的离心率. 用 e 表示,e = 1.探究如果抛物线的标准方程是〖 y〗^2=-2px(p>0), ②〖 x〗^2=2py(p>0), ③〖 x〗^2=-2py(p>0), ④
∵在△EFP中,|EF|=2c,EF上的高为点P的纵坐标,∴S△EFP=4/3c2=12,∴c=3,即P点坐标为(5,4).由两点间的距离公式|PE|=√("(" 5+3")" ^2+4^2 )=4√5,|PF|=√("(" 5"-" 3")" ^2+4^2 )=2√5,∴a=√5.又b2=c2-a2=4,故所求双曲线的方程为x^2/5-y^2/4=1.5.求适合下列条件的双曲线的标准方程.(1)两个焦点的坐标分别是(-5,0),(5,0),双曲线上的点与两焦点的距离之差的绝对值等于8;(2)以椭圆x^2/8+y^2/5=1长轴的端点为焦点,且经过点(3,√10);(3)a=b,经过点(3,-1).解:(1)由双曲线的定义知,2a=8,所以a=4,又知焦点在x轴上,且c=5,所以b2=c2-a2=25-16=9,所以双曲线的标准方程为x^2/16-y^2/9=1.(2)由题意得,双曲线的焦点在x轴上,且c=2√2.设双曲线的标准方程为x^2/a^2 -y^2/b^2 =1(a>0,b>0),则有a2+b2=c2=8,9/a^2 -10/b^2 =1,解得a2=3,b2=5.故所求双曲线的标准方程为x^2/3-y^2/5=1.(3)当焦点在x轴上时,可设双曲线方程为x2-y2=a2,将点(3,-1)代入,得32-(-1)2=a2,所以a2=b2=8.因此,所求的双曲线的标准方程为x^2/8-y^2/8=1.当焦点在y轴上时,可设双曲线方程为y2-x2=a2,将点(3,-1)代入,得(-1)2-32=a2,a2=-8,不可能,所以焦点不可能在y轴上.综上,所求双曲线的标准方程为x^2/8-y^2/8=1.
1.判断 (1)椭圆x^2/a^2 +y^2/b^2 =1(a>b>0)的长轴长是a. ( )(2)若椭圆的对称轴为坐标轴,长轴长与短轴长分别为10,8,则椭圆的方程为x^2/25+y^2/16=1. ( )(3)设F为椭圆x^2/a^2 +y^2/b^2 =1(a>b>0)的一个焦点,M为其上任一点,则|MF|的最大值为a+c(c为椭圆的半焦距). ( )答案:(1)× (2)× (3)√ 2.已知椭圆C:x^2/a^2 +y^2/4=1的一个焦点为(2,0),则C的离心率为( )A.1/3 B.1/2 C.√2/2 D.(2√2)/3解析:∵a2=4+22=8,∴a=2√2.∴e=c/a=2/(2√2)=√2/2.故选C.答案:C 三、典例解析例1已知椭圆C1:x^2/100+y^2/64=1,设椭圆C2与椭圆C1的长轴长、短轴长分别相等,且椭圆C2的焦点在y轴上.(1)求椭圆C1的半长轴长、半短轴长、焦点坐标及离心率;(2)写出椭圆C2的方程,并研究其性质.解:(1)由椭圆C1:x^2/100+y^2/64=1,可得其半长轴长为10,半短轴长为8,焦点坐标为(6,0),(-6,0),离心率e=3/5.(2)椭圆C2:y^2/100+x^2/64=1.性质如下:①范围:-8≤x≤8且-10≤y≤10;②对称性:关于x轴、y轴、原点对称;③顶点:长轴端点(0,10),(0,-10),短轴端点(-8,0),(8,0);④焦点:(0,6),(0,-6);⑤离心率:e=3/5.
二、探究新知一、点到直线的距离、两条平行直线之间的距离1.点到直线的距离已知直线l的单位方向向量为μ,A是直线l上的定点,P是直线l外一点.设(AP) ?=a,则向量(AP) ?在直线l上的投影向量(AQ) ?=(a·μ)μ.点P到直线l的距离为PQ=√(a^2 "-(" a"·" μ")" ^2 ).2.两条平行直线之间的距离求两条平行直线l,m之间的距离,可在其中一条直线l上任取一点P,则两条平行直线间的距离就等于点P到直线m的距离.点睛:点到直线的距离,即点到直线的垂线段的长度,由于直线与直线外一点确定一个平面,所以空间点到直线的距离问题可转化为空间某一个平面内点到直线的距离问题.1.已知正方体ABCD-A1B1C1D1的棱长为2,E,F分别是C1C,D1A1的中点,则点A到直线EF的距离为 . 答案: √174/6解析:如图,以点D为原点,DA,DC,DD1所在直线分别为x轴、y轴、z轴建立空间直角坐标系,则A(2,0,0),E(0,2,1),F(1,0,2),(EF) ?=(1,-2,1),
本节课选自《普通高中课程标准实验教科书数学必修1本(A版)》第五章的5.5.1 两角和与差的正弦、余弦和正切公式。本节的主要内容是由两角差的余弦公式的推导,运用诱导公式、同角三角函数的基本关系和代数变形,得到其它的和差角公式。让学生感受数形结合及转化的思想方法。发展学生数学直观、数学抽象、逻辑推理、数学建模的核心素养。课程目标 学科素养1.了解两角差的余弦公式的推导过程.2.掌握由两角差的余弦公式推导出两角和的余弦公式及两角和与差的正弦、正切公式.3.熟悉两角和与差的正弦、余弦、正切公式的灵活运用,了解公式的正用、逆用以及角的变换的常用方法.4.通过正切函数图像与性质的探究,培养学生数形结合和类比的思想方法。 a.数学抽象:公式的推导;b.逻辑推理:公式之间的联系;c.数学运算:运用和差角角公式求值;d.直观想象:两角差的余弦公式的推导;e.数学建模:公式的灵活运用;
新知讲授(一)——随机试验 我们把对随机现象的实现和对它的观察称为随机试验,简称试验,常用字母E表示。我们通常研究以下特点的随机试验:(1)试验可以在相同条件下重复进行;(2)试验的所有可能结果是明确可知的,并且不止一个;(3)每次试验总是恰好出现这些可能结果中的一个,但事先不确定出现哪个结果。新知讲授(二)——样本空间思考一:体育彩票摇奖时,将10个质地和大小完全相同、分别标号0,1,2,...,9的球放入摇奖器中,经过充分搅拌后摇出一个球,观察这个球的号码。这个随机试验共有多少个可能结果?如何表示这些结果?根据球的号码,共有10种可能结果。如果用m表示“摇出的球的号码为m”这一结果,那么所有可能结果可用集合表示{0,1,2,3,4,5,6,7,8,9}.我们把随机试验E的每个可能的基本结果称为样本点,全体样本点的集合称为试验E的样本空间。
Activity 4: Figuring out the structure and the writing purpose 本活动为实现课时目标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.) 【设计意图】 步骤1旨在预测和验证文章最后一段主要内容,梳理完整的语篇结构,步骤2旨在思考和讨论作者的写作目的。教师也可根据学生课堂反应情况融入对语篇人称多次转换的思考。
本活动旨在落实课时目标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,【设计意图】此任务旨在迁移一、二课时所学,解决实际问题。学生对比自己经历过的挑战或挫折,写信给学生会申请前往贵州担任短期支教教师,把个人以前是怎么战胜挫折的经过书写出来。结合所学,迁移创新,分析解决自身实际问题,在真实情境中学生通过仿写进行主题语言的精确输出。完成任务的过程中,能较多地使用已学语言、内容、结构和写作手法来描述自己面对挫折的处理方式、态度和应有的品质,近一步激发学生树立正确的价值观,学会逆境出人才,坚忍不拔,从容不迫,又做到谦让、分享和合作。课后学生修正习作,再次提交。
本活动旨在落实课时目标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? 【设计意图】该活动是一个完全开放性的活动,每个学生都会有不同的答案。运用迁移所学,自由口头表达自己对海洋探索的态度。对于中国海洋探索的未来,每个人的想法是不一样的,有乐观,有担忧,有认为值得投入,也有认为不值得付出太大代价,这里给学生自由表达的空间只要学会有支撑自己观点的事实就可以了,进一步培养学生批判性思维和正确的价值观。 Assignment: 此任务旨在迁移一、二课时所学,培养学生辩证分析问题的能力。 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.
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.【设计意图】学生寻找和梳理公园历史上的重要事件,体会人与自然的和谐关系,评鉴介绍性语言的特点。【核心素养提升点】发展自主提取、梳理文本信息能力,训练逻辑思维和高阶思维。Activity 3: Highlighting the secret of the text
[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. 【设计意图】主题类语言整理有助于学生类化语言应用,提高语言输出的丰富性。处理完文本内容信息后,进入语篇信息处理,进行主题相关的词块归类。引导学生快速阅读,寻找表达相同主题(发展或者艺术)的词和短语,再根据词性、用法和结构进行归类,储备主题相关词汇,丰富语言储备,提升语言素养。 Assignment: Go online to gather more information about Chinese painting and write a short history of it. 【设计意图】结合所学,迁移运用,根据实际语境,进行模仿性运用。在此过程中,学生尝试借鉴已学的语言、内容、语篇结构和写作手法来建构新文本,实现语篇输出,同时关注中西艺术文化的差别,加深对优秀文化的认同,培养文化意识。
本单元阅读文本介绍了几种简单的英语诗歌形式,旨在让学生能理解和欣赏英语诗歌的美,包括形式美、内容美、意义美,培养审美情趣,并从作品的意义美中获得积极的人生态度和价值观念启示。 该文本是一则典型的说明性文本,用简单易懂的语言向英语诗歌的初学者们介绍了五种比较简单的英语诗歌形式。文题“A Few Simple Forms of English Poems”是整个文本的核心话题。正文内容共七段,按“总—分—总”建构。第一段为总起段,概述了英语诗歌的创作原因以及主要特点,涉及了形式、内容、意义等方面赏析英语诗歌的几个主要维度;第二段至第六段分别介绍了童谣、清单诗、五行诗、俳句和唐诗五种英语诗歌形式;第七段收尾,鼓励读者尝试英语诗歌创作。 在进行文本教学设计时,要引导学生梳理关于与诗歌要素和诗歌赏析有关的话题类语言,既包括format、rhythm、subject、image等名词,也包括have a strong rhythm、be made up of、contain、consist of、convey这样的动词和动词短语。
帮助学生通过讨论与对主题的提升,反思自己的旅游方式,以便做出更优化的安排,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 本活动为实现课时教学目标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
【设计意图】以“新科技是一把双刃剑”为主题开展讨论活动。这个话题比较大,所以给了一定的限制,首先需要以智能家居为例来阐述科技发展对未来生活产生的影响,然后列举其优点和缺点,最后就以上现象发表自己的观点。这个活动是对整个文本的创意性总结与意义的升华,留给学生一定的想象空间,学生借此机会可以运用文本内容和语言表达自己对科技发展的看法和态度。Assignments:1. Finish Exercise 4 on Page 15 of the textbook.A smart home is one that integrated computers into the structure of the building itself. In this way, many of the things that we now do ourselves become automatic. For example, the smart home could control the air conditioning and lights so that you would no longer have to turn switches on and off, and so that your home would be more energy-efficient. The smart home could also monitor itself to make sure that everything is working as it should, and send you warnings if there is a problem. Such smart homes could even be programmed to detect your health problems, and then give you reasonable advice as to the food you should eat or if you should see a doctor. So, in a sense, smart homes will lead us to living smarter lives.2.Create a smart function for your home, and share your creation in the next period.
一、激趣导入 多媒体显示写杜甫的对联: 诗史数千言,秋天一鹄先生骨;草堂三五里,春水群殴野老心。 1、提问:同学们知道这幅对联是写谁的吗?请大家回忆一下我们学过他的那些作品?能背诵一首我们共同欣赏吗?(学生背诵)今天我们来学习他的另一首诗歌《登高》(板书)
月球对地球的意义月球与地球形影相随,关系密切。月球对地球的影响,主要有以下几方面:1.地球上夜晚的自然照明,主要靠月亮。2.远在古代,人们就根据月相变化的周期,编订历法。我国农历月份的安排,是以月相变化 周期为标准的。农历规定朔为初一,这样,望就在十五日或十六日。我国人民的传统节日,像春节、中秋节就是按农历的月日计算安排的。3.由于地球表面各处所受月球和太阳引力的不同,地球上的水体产生了明显的潮汐现象。4.月球是人类星际航行的第一站。已知月球表面有多种宝贵矿藏;重力较小;没有大气层,利用太阳能的条件较好。如何利用月球的特殊环境,开发月球的资源,以及如 何利用月球作“码头”,使人类更好地研究宇宙,这将是月地关系的新篇章。
5.对土星五号火箭和登月舱的质疑现代航天飞机只能把20吨载荷送上低轨,而当 年的土星五号却能轻而易举地把100吨以上载荷送上地球轨道,将几十吨物体推出地球重力圈,为什么后来却弃而不用,据说连图纸都没有保存下来?6.温度对摄影器材的影响月面白天可达到121°C,据图片看,相机是露在宇航服外而没有采用保温措施的。胶卷在66°C就会受热卷曲失效,怎么拍得了照片?这些人士认为,对以上这一切美国政府一直没个 交代,而知情者由于担心生活和安全受到影响,甚至可能直接遭到了胁迫,至今对此沉默不言。但相信不久的将来,诞生于美苏太空竞赛年代的“登月骗局”定会水落石出。反驳不过,也有许多人认为“阿波罗”登月计划不可能造假:首先因为该计划当时是在全球实况转播的,近亿人亲眼看到。另外,宇航员还从月球带回了一些实物,如岩石。
(2)、中国坚持以互利合作实现共同繁荣----促进共同发展中国坚持以互利合作实现共同繁荣。中国连续担任经社理事会理事国,积极参与经社系统有关经济和社会发展的重要国际会议和其他活动并承办了联合国第四次世界妇女大会。中国积极推动南北对话和南南合作,敦促发达国家为实现全球普遍、协调、均衡发展承担更多责任。中国加人多项国际人权公约并认真履行公约义务,与联合国人权事务高级专员保持良好合作,与多国展开人权对话。相关链接:1995年9月,联合国第四次世界妇女大会在北京举行。来自197个国家和地区以及众多国际组织的1.76万名代表围绕会议主题“以行动谋求平等、发展与和平”展开热烈讨论。会议通过了《北京宣言》和《行动纲领》,为全球妇女事业的发展注入了新的活力。