一、情境导学在一条笔直的公路同侧有两个大型小区,现在计划在公路上某处建一个公交站点C,以方便居住在两个小区住户的出行.如何选址能使站点到两个小区的距离之和最小?二、探究新知问题1.在数轴上已知两点A、B,如何求A、B两点间的距离?提示:|AB|=|xA-xB|.问题2:在平面直角坐标系中能否利用数轴上两点间的距离求出任意两点间距离?探究.当x1≠x2,y1≠y2时,|P1P2|=?请简单说明理由.提示:可以,构造直角三角形利用勾股定理求解.答案:如图,在Rt △P1QP2中,|P1P2|2=|P1Q|2+|QP2|2,所以|P1P2|=?x2-x1?2+?y2-y1?2.即两点P1(x1,y1),P2(x2,y2)间的距离|P1P2|=?x2-x1?2+?y2-y1?2.你还能用其它方法证明这个公式吗?2.两点间距离公式的理解(1)此公式与两点的先后顺序无关,也就是说公式也可写成|P1P2|=?x2-x1?2+?y2-y1?2.(2)当直线P1P2平行于x轴时,|P1P2|=|x2-x1|.当直线P1P2平行于y轴时,|P1P2|=|y2-y1|.
一、情境导学前面我们已经得到了两点间的距离公式,点到直线的距离公式,关于平面上的距离问题,两条直线间的距离也是值得研究的。思考1:立定跳远测量的什么距离?A.两平行线的距离 B.点到直线的距离 C. 点到点的距离二、探究新知思考2:已知两条平行直线l_1,l_2的方程,如何求l_1 〖与l〗_2间的距离?根据两条平行直线间距离的含义,在直线l_1上取任一点P(x_0,y_0 ),,点P(x_0,y_0 )到直线l_2的距离就是直线l_1与直线l_2间的距离,这样求两条平行线间的距离就转化为求点到直线的距离。两条平行直线间的距离1. 定义:夹在两平行线间的__________的长.公垂线段2. 图示: 3. 求法:转化为点到直线的距离.1.原点到直线x+2y-5=0的距离是( )A.2 B.3 C.2 D.5D [d=|-5|12+22=5.选D.]
1.直线2x+y+8=0和直线x+y-1=0的交点坐标是( )A.(-9,-10) B.(-9,10) C.(9,10) D.(9,-10)解析:解方程组{■(2x+y+8=0"," @x+y"-" 1=0"," )┤得{■(x="-" 9"," @y=10"," )┤即交点坐标是(-9,10).答案:B 2.直线2x+3y-k=0和直线x-ky+12=0的交点在x轴上,则k的值为( )A.-24 B.24 C.6 D.± 6解析:∵直线2x+3y-k=0和直线x-ky+12=0的交点在x轴上,可设交点坐标为(a,0),∴{■(2a"-" k=0"," @a+12=0"," )┤解得{■(a="-" 12"," @k="-" 24"," )┤故选A.答案:A 3.已知直线l1:ax+y-6=0与l2:x+(a-2)y+a-1=0相交于点P,若l1⊥l2,则点P的坐标为 . 解析:∵直线l1:ax+y-6=0与l2:x+(a-2)y+a-1=0相交于点P,且l1⊥l2,∴a×1+1×(a-2)=0,解得a=1,联立方程{■(x+y"-" 6=0"," @x"-" y=0"," )┤易得x=3,y=3,∴点P的坐标为(3,3).答案:(3,3) 4.求证:不论m为何值,直线(m-1)x+(2m-1)y=m-5都通过一定点. 证明:将原方程按m的降幂排列,整理得(x+2y-1)m-(x+y-5)=0,此式对于m的任意实数值都成立,根据恒等式的要求,m的一次项系数与常数项均等于零,故有{■(x+2y"-" 1=0"," @x+y"-" 5=0"," )┤解得{■(x=9"," @y="-" 4"." )┤
解析:①过原点时,直线方程为y=-34x.②直线不过原点时,可设其方程为xa+ya=1,∴4a+-3a=1,∴a=1.∴直线方程为x+y-1=0.所以这样的直线有2条,选B.答案:B4.若点P(3,m)在过点A(2,-1),B(-3,4)的直线上,则m= . 解析:由两点式方程得,过A,B两点的直线方程为(y"-(-" 1")" )/(4"-(-" 1")" )=(x"-" 2)/("-" 3"-" 2),即x+y-1=0.又点P(3,m)在直线AB上,所以3+m-1=0,得m=-2.答案:-2 5.直线ax+by=1(ab≠0)与两坐标轴围成的三角形的面积是 . 解析:直线在两坐标轴上的截距分别为1/a 与 1/b,所以直线与坐标轴围成的三角形面积为1/(2"|" ab"|" ).答案:1/(2"|" ab"|" )6.已知三角形的三个顶点A(0,4),B(-2,6),C(-8,0).(1)求三角形三边所在直线的方程;(2)求AC边上的垂直平分线的方程.解析(1)直线AB的方程为y-46-4=x-0-2-0,整理得x+y-4=0;直线BC的方程为y-06-0=x+8-2+8,整理得x-y+8=0;由截距式可知,直线AC的方程为x-8+y4=1,整理得x-2y+8=0.(2)线段AC的中点为D(-4,2),直线AC的斜率为12,则AC边上的垂直平分线的斜率为-2,所以AC边的垂直平分线的方程为y-2=-2(x+4),整理得2x+y+6=0.
解析:当a0时,直线ax-by=1在x轴上的截距1/a0,在y轴上的截距-1/a>0.只有B满足.故选B.答案:B 3.过点(1,0)且与直线x-2y-2=0平行的直线方程是( ) A.x-2y-1=0 B.x-2y+1=0C.2x+y=2=0 D.x+2y-1=0答案A 解析:设所求直线方程为x-2y+c=0,把点(1,0)代入可求得c=-1.所以所求直线方程为x-2y-1=0.故选A.4.已知两条直线y=ax-2和3x-(a+2)y+1=0互相平行,则a=________.答案:1或-3 解析:依题意得:a(a+2)=3×1,解得a=1或a=-3.5.若方程(m2-3m+2)x+(m-2)y-2m+5=0表示直线.(1)求实数m的范围;(2)若该直线的斜率k=1,求实数m的值.解析: (1)由m2-3m+2=0,m-2=0,解得m=2,若方程表示直线,则m2-3m+2与m-2不能同时为0,故m≠2.(2)由-?m2-3m+2?m-2=1,解得m=0.
【课件展示】《秦朝中央集权制度的建立》《教材简析》《教学目标》《教法简介》《教学过程设计及特色简述》【师】本节内容以秦代政治体制和官僚系统的建立为核心内容,主要包括秦朝中央集权制的建立的背景、建立过程及影响。本节内容在整个单元中起到承前启后的作用,在整个模块中也有相当重要的地位。让学生了解中国古代中央集权政治体制的初建对于理解我国古代政治制度的发展乃至我们今天的政治体制是十分必要的。 本堂课我采用多媒体和讲授法及历史辩论法相结合,通过巧妙设计问题情境,调动学生的学习积极性,使学生主动学习,探究思考。教师引导和组织学生采取小组讨论、情景体验等方式,达到教学目标。 本节内容分三个部分,下面首先看秦朝中央集权制度建立的前提即秦的统一
二、教学目标:1、知识与能力(1)了解我国古代冶金、制瓷、丝织业发展的基本情况;(2)了解中国古代手工业享誉世界的史实,培养学生的民族自信心。2、过程与方法(1)通过大量的历史图片,指导学生欣赏一些精湛的手工业艺术品,提高学生探究古代手工业的兴趣;(2)运用历史材料引导学生归纳古代手工业产品的基本特征。3、情感态度与价值观:通过本课教学,使学生充分地感受到我国古代人民的聪明与才智,认识到古代许多手工业品具有较高的艺术价值,以及在世界上的领先地位和对世界文明的影响,增强民族自豪感。
设计意图:几道例题及练习题,其中例1小车由静止启动开始行驶,以加速度 做匀加速运动,求2s后的速度大小?进而变式到:小车遇到红灯刹车……,充分体现了“从生活到物理,从物理到社会”的物理教学理念;例题及练习题由浅入深、由易到难、各有侧重,体现新课标提出的让不同的学生在物理上得到不同发展的教学理念。这一环节总的设计意图是反馈教学,内化知识。(6) 小结归纳,拓展深化我的理解是,小结归纳不应该仅仅是知识的简单罗列,而应该是优化认知结构,完善知识体系的一种有效手段,为充分发挥学生的主题作用,从学习的知识、方法、体验是那个方面进行归纳,我设计了这么三个问题:① 通过本节课的学习,你学会了哪些知识;② 通过本节课的学习,你最大的体验是什么;③ 通过本节课的学习,你掌握了哪些学习物理的方法?
培养学生合作交流意识和探究问题的能力,这一部分知识层层递进,符合学生由特殊到一般、由简单到复杂的认知规律。4、互动探究(1)极限思想的渗透让学生阅读“思考与讨论”小版块.培养学生的自学和阅读能力提出下列问题,进行分组讨论:a、用课本上的方法估算位移,其结果比实际位移大还是小?为什么?b、为了提高估算的精确度,时间间隔小些好还是大些好?为什么?针对学生回答的多种可能性加以评价和进一步指导。让学生从讨论的结果中归纳得出:△t越小,对位移的估算就越精确。渗透极限的思想。通过小组内分工合作,讨论交流,培养学生交流合作的精神,以及搜集信息、处理信息的能力;通过小组间对比总结,使学生学会在对比中发现问题,在解决问题过程中提高个人能力;
谈到志愿者,相信大家并不陌生。联合国将它定义为“不以利益、金钱、扬名为目的,而是为了近邻乃至全世界进行贡献的活动者”,并于1985年12月17日,第40届联合国大会上,把每年12月5日定为“国际志愿者日”,目的是为了在全世界范围内弘扬志愿者精神。如今已有100多个国家积极响应,我国也在此之列。中国是礼仪之邦,自古就有“君子贵人贱己,先人而后己”之说,依靠自己的力量去帮助他人,将爱的温暖在人与人之间传递,让社会更和谐,这本身也是个人价值的社会体现,又何乐而不为呢?我们都还记得那不平凡的XX年,中国经历的年初的特大雪灾,地震和8月在京举行的奥林匹克运动会。这些考验,向全世界展示了一个崛起强国的巨大力量,和国人伟大的民族精神。在这些重大事件中,都可以见到活跃着的一些身影,是的,他们是志愿者。他们奋不顾身赶赴灾区,运输救灾物质,帮助受难群众。他们不计名利,默默奉献,为人们重建家园,他们用爱心、关怀、抚慰人们受伤的心灵。他们以热情、礼貌、智慧向来自四面八方的宾朋展示中国的魅力。当我们再回想起这一幕幕场景时,怎能忘记这些可爱的志愿者们,所付出的一切呢?
(六)6月份以来在FMXXX交通广播分别在早、中、晚高峰时段循环播放致全州无偿献血者的感谢语、无偿献血政策宣传等相关内容。(七)通过血站管理信息系统向在我站参加无偿献血的献血者发送节日祝福短信15万余条。(八)6月份来通过我站微信公众号在“高校专栏”开展高校无偿献血知识问卷调查,分别在XX学院、XX职业技术学院、XX职业技术学院等院校进行,目的是进一步了解青年学生献血动机、科普献血知识,为以后高校无的偿献血工作开展提供指导。(九)世界献血者日前夕,我站制定了“纪念第二十个世界献血者日”纪念奖杯500份,并于6月13-14日当天在各献血点发放,让献血更有“纪念”价值。四、硕果成效显著,促进献血事业(一)从6月12日到6月15日开展世界献血者日宣传活动以来,前到我站成功献血达733人次,合计献血量1217U。
人教版新课标教材必修一的“表达交流”部分,有一个专题是“人性的光辉——写人要凸显个性”。其中的“写法借鉴”部分列举了两则人物描写实例,并归纳出人物描写的几个要点。其训练的思路和方法是很明显的,但所列举的人物描写的实例却不够典型。而必修一第三单元正好是学习写人记事散文,其中的两篇自读课文《记梁任公先生的一次演讲》《金岳霖先生》又是写人记事非常典型的文章,故而我尝试将这两篇文章作为实例和。写人要凸显个性。写作指导结合起来教学。这样设计还有一个目的,那就是解决课程改革中教学内容多而课时紧张的矛盾,提高课堂教学效率。师:今天,我们一起来学习“写人要凸显个性”。这两堂课分四个步骤来完成:一、先学习教材中关于写人方法的介绍,约15分钟;二、快速阅读第三单元的《记梁任公先生的一次演讲》和《金岳霖先生》两篇文章,具体感受其写人的方法,约30分钟;
师:在科学发展过程中,前一个理论体系的不完善之处,往往是新的研究和新的发现的突破口。开普勒之后,意大利天文学家伽利略创制了天文望远镜,用更加精确的观察继续发展和验证哥白尼创立的新天文学理论。除了用望远镜进行天文观察以外,伽利略还开始进行自然科学的实验研究,哪位同学能给大家讲一讲伽利略在比萨斜塔上所作的关于物体自由下落的实验?生:(讲述这一实验)师:所以,伽利略在科学方面更加重要的贡献是奠定了近代实验科学的基础。(2)实验科学和唯物主义师:伽利略从实践上开辟了实验科学的方法,而英国唯物主义哲学家培根则从理论上阐述了实验科学的方法——归纳法。培根和伽利略同被称为实验科学之父,培根还有一句影响深刻的名言:“知识就是力量”,表明了他注重知识,尊崇科学的精神。我们再来概括一下意大利哲学家布鲁诺的唯物主义思想,是否有同学可以简述布鲁诺的生平事迹?
The theme of this section is “Talk about festival activities and festival experiences”.Festival and holiday is a relaxing and interesting topic for students. This part talks about the topic from the daily life of students’. In the part A ---Listening and Speaking, there are three conversations among different speakers from three countries(Japan, Rio and China), where the speakers are participating in or going to participate in the festivals and celebrations. So listening for the relationship among them is a fundamental task. Actually, with the globalization and more international communication, it is normal for Chinese or foreigners to witness different festivals and celebrations in or out of China. In the Conversation 1, a foreign reporter is interviewing a Japanese young girl who just had participated in the ceremony of the Coming-of-Age Day on the street and asking her feeling about the ceremony and the afterwards activities. Conversation 2, Chinese girl Li Mei is witnessing the Rio Carnival for the first time, and her friend Carla gives her some advice on the costumes which enables her to match with the carnival to have a good time. Conversation 3, a Chinese guide is showing a group of foreign visitors around the Lantern Festival and introducing the customs of the festival to them. The three conversations have a strong vitality and insert the festival and cultural elements from different countries. So perceiving the festivals and cultures from different countries is the second task. At the same time, the scripts also insert the targeted grammar --- v-ing as attributive and predicative, which students can perceive and experience in a real context and make a road for the further study. That is the third task. In the Part B--- Listening and Talking, the theme is “Talk about festival experience”, which is the common topic in our daily conversations. During the conversation, Song Lin, a Chinese student, asked Canadian friend Max about how to spend Christmas. In the conversation, Song Lin talked about experience and the feelings during the Chinese Spring Festival, during which there are not only some enjoyable things but some unpleasant things. After the listening, perhaps students find there are some similarities between Christmas and the Chinese Spring Festival as there are some differences in the origins and celebrations. For example, people always visit friends and relatives, decorate their houses, have a big dinner together, chat and give presents to each other.
Example:One day, a poor boy who was trying to pay his way through school by sending newspapers door to door found that he only had one dime(一角)left. He was so hungry that he decided to beg for a meal at the next house.However, he lost his nerve when a lovely young woman opened the door. Instead of a meal he asked for a drink of water. She thought he looked hungry so she brought him a large glass of milk. He drank it slowly, and then asked, “How much do I owe you?” “You don’t owe me anything,” she replied, “Mother has taught me never to accept pay for a kindness.” “Then I thank you from the bottom of my heart.” With these words, Howard Kelly left that house.Years later the woman became badly ill and was finally sent to the hospital in a big city. Dr. Howard Kelly, now famous, was called in. When he heard the name of the town she came from, a strange light filled his eyes. Dressed in his doctor’s clothes, Dr. Kelly went into her room and recognized her at once. From that day on, he gave special attention to her, and decided to do his best to save her life.At last the woman was saved. Dr. Kelly asked the business office to pass the final bill to him. He looked at it and then wrote something on the side. The bill was sent to the woman’s room. She was afraid to open it because she was sure that it would take the rest of her life to pay for it off. Finally she looked, and the note on the side of the bill caught her attention. She read these words: “Paid in full with a glass of milk, Dr. Howard Kelly.” Tear of joy flooded her eyes.
The topic of this part is “Describe a place with distinctive cultural identity”.This section focuses on Chinese culture by introducing Chinatown, whose purpose is to show the relationship between the Chinese culture and American culture. The Chinese culture in Chinatown is an important part of American culture. Chinatown is an important window of spreading Chinese culture and the spirit homeland of oversea Chinese, where foreigners can experience Chinese culture by themselves.Concretely, the title is “Welcome to Chinatown!”, from which we can know that the article aims at introducing Chinatown. The author used the “Introduction--Body Paragraph--Conclusion” to describe the people, language, architecture, business, famous food and drinks and people’s activities, which can be a centre for Chinese culture and shows its unique charm.1. Read quickly to get main idea; read carefully to get the detailed information.2. Learn the characteristics of writing and language.3. Learn to introduce your own town according to the text.4. Learn to correct others’ writing.1. Learn the characteristics of writing and language.2. Learn to introduce your own town according to the text.Step 1 Lead in ---Small talkIn the reading part, we mentioned the Chinatown of San Francisco. How much do you know about Chinatown of San Francisco ?Chinatown is a main living place for Chinese immigrants, where you can see many Chinese-style buildings, costumes, operas, restaurants, music and even hear Chinese.Step 2 Before reading ---Predict the contentWhat is the writer’s purpose of writing this text ? How do you know ?From the title(Welcome to Chinatown) and some key words from the text(tourist, visit, visitors, experience), we can know the purpose of the text is to introduce Chinatown and show the relationship between Chinese culture and American culture.
Discuss these questions in groups.Q1: Have you ever been to a place that has a diverse culture ? What do you think about the culture diversity ?One culturally diverse place that I have been to is Harbin, the capital city of Heilongjiang Province. I went there last year with my family to see the Ice and Snow Festival, and I was amazed at how the culture as different to most other Chinese cities. There is a big Russian influence there, with beautiful Russian architecture and lots of interesting restaurants. I learnt that Harbin is called “the Oriental Moscow” and that many Russians settled there to help build the railway over 100 years ago.Q2: What are the benefits and challenges of cultural diversity ?The benefits: People are able to experience a wide variety of cultures, making their lives more interesting, and it can deepen the feelings for our national culture, it is also helpful for us to learn about other outstanding culture, which helps improve the ability to respect others. The challenges: People may have trouble communicating or understanding each other, and it may lead to disappearance of some civilizations and even make some people think “The western moon is rounder than his own.”Step 7 Post reading---RetellComplete the passage according to the text.Today, I arrived back in San Francisco, and it feels good (1) _____(be) back in the city again. The city succeeded in (2)_________ (rebuild) itself after the earthquake that (3)________ (occur) in 1906, and I stayed in the Mission District, enjoying some delicious noodles mixed with cultures. In the afternoon, I headed to a local museum (4)____ showed the historical changes in California. During the gold rush, many Chinese arrived, and some opened up shops and restaurants in Chinatown to earn a (5)_____ (live). Many others worked on (6)______ (farm), joined the gold rush, or went to build the railway that connected California to the east. The museum showed us (7)____ America was built by immigrants from (8)________ (difference) countries and cultures. In the evening, I went to Chinatown, and ate in a Cantonese restaurant that served food on (9)________(beauty) china plates. Tomorrow evening, I’m going to (10)__ jazz bar in the Richmond District. 答案:1. to be 2. rebuilding 3. occurred 4. that 5.living6. farms 7.how 8. different 9. beautiful 10. a
Step 3 Meaning1. 过去将来时表示从过去某一时间来看将要发生的动作或存在的状态, 常用在宾语从句中。一般由“would/should +动词原形”构成。She hoped that they would meet again someday. 她希望将来有一天他们能再见面。2. was/were going to+动词原形: 表示过去将要发生或很有可能发生的动作, 常用于口语中, 表示预言、意图或者打算等。He was going to start work the following week. 他打算下星期开始工作。3. was/were about to do: 常用来表示即将发生的动作, “刚要/正要做……”。注意该结构不与任何时间状语连用。I felt that something terrible was about to happen. 我感到某种可怕的事情即将发生。4.was/were to do: 表示“曾计划做某事”, 如果表示“本来计划做某事, 动作没实现”, 则需用 “was/were to have done”。She said she was to have told me about the accident. 她说她本来想告诉我关于事故的事。5.Start, go, come, leave, see, meet等动词的过去进行时: 表示就过去某一时刻而言即将发生的动作。She was coming later. 她随后就来。I had just put on my overcoat and was leaving to visit a friend of mine. 我刚穿上外套要去看我的一个朋友。
导语在必修第一册中,我们研究了函数的单调性,并利用函数单调性等知识,定性的研究了一次函数、指数函数、对数函数增长速度的差异,知道“对数增长” 是越来越慢的,“指数爆炸” 比“直线上升” 快得多,进一步的能否精确定量的刻画变化速度的快慢呢,下面我们就来研究这个问题。新知探究问题1 高台跳水运动员的速度高台跳水运动中,运动员在运动过程中的重心相对于水面的高度h(单位:m)与起跳后的时间t(单位:s)存在函数关系h(t)=-4.9t2+4.8t+11.如何描述用运动员从起跳到入水的过程中运动的快慢程度呢?直觉告诉我们,运动员从起跳到入水的过程中,在上升阶段运动的越来越慢,在下降阶段运动的越来越快,我们可以把整个运动时间段分成许多小段,用运动员在每段时间内的平均速度v ?近似的描述它的运动状态。
4.That was an experience that frightened everyone. →That was _____________________. 答案:1. taking 2. being discussed 3. in the reading room 4. a frightening experienceStep 6 The meaning and function of V-ing as the predicative动词-ing形式作表语,它通常位于系动词后面,用以说明主语“是什么”或“怎么样”一种表示主语的特质、特征和状态, 其作用相当于形容词; 另一种具体说明主语的内容, 即主语等同于表语, 两者可互换。The music they are playing sounds so exciting. 他们演奏的音乐听起来令人激动。The result is disappointing. 结果令人失望。Our job is playing all kinds of music. 我们的工作就是演奏各种音乐。Seeing is believing. 眼见为实。Step 7 Practice1. It is ________(amaze) that the boy is able to solve the problem so quickly.2. Buying a car is simply _______(waste) money. 3. Please stop making the noise—it’s getting ________(annoy). 4. complete the passage with the appropriate -ing form.La Tomatina is a festival that takes place in the Spanish town Bunol every August. I think many food festivals are __________ because people are just eating. however, this festival is _________ because people don't actually eat the tomatoes. Instead, they throw them at each other! the number of people ________ part in this tomato fight, can reach up to 20,000, and it is a very __________ fight that lasts for a whole hour. The _______ thing is how clean Bunol is after the tomatoes are washed away after the fight. this is because the juice form tomatoes is really good for making surfaces clean!答案:1. amazing 2. wasting 3. annoying4. boring interesting taking exciting amazing