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直线与圆的位置关系教学设计人教A版高中数学选择性必修第一册
切线方程的求法1.求过圆上一点P(x0,y0)的圆的切线方程:先求切点与圆心连线的斜率k,则由垂直关系,切线斜率为-1/k,由点斜式方程可求得切线方程.若k=0或斜率不存在,则由图形可直接得切线方程为y=b或x=a.2.求过圆外一点P(x0,y0)的圆的切线时,常用几何方法求解设切线方程为y-y0=k(x-x0),即kx-y-kx0+y0=0,由圆心到直线的距离等于半径,可求得k,进而切线方程即可求出.但要注意,此时的切线有两条,若求出的k值只有一个时,则另一条切线的斜率一定不存在,可通过数形结合求出.例3 求直线l:3x+y-6=0被圆C:x2+y2-2y-4=0截得的弦长.思路分析:解法一求出直线与圆的交点坐标,解法二利用弦长公式,解法三利用几何法作出直角三角形,三种解法都可求得弦长.解法一由{■(3x+y"-" 6=0"," @x^2+y^2 "-" 2y"-" 4=0"," )┤得交点A(1,3),B(2,0),故弦AB的长为|AB|=√("(" 2"-" 1")" ^2+"(" 0"-" 3")" ^2 )=√10.解法二由{■(3x+y"-" 6=0"," @x^2+y^2 "-" 2y"-" 4=0"," )┤消去y,得x2-3x+2=0.设两交点A,B的坐标分别为A(x1,y1),B(x2,y2),则由根与系数的关系,得x1+x2=3,x1·x2=2.∴|AB|=√("(" x_2 "-" x_1 ")" ^2+"(" y_2 "-" y_1 ")" ^2 )=√(10"[(" x_1+x_2 ")" ^2 "-" 4x_1 x_2 "]" ┴" " )=√(10×"(" 3^2 "-" 4×2")" )=√10,即弦AB的长为√10.解法三圆C:x2+y2-2y-4=0可化为x2+(y-1)2=5,其圆心坐标(0,1),半径r=√5,点(0,1)到直线l的距离为d=("|" 3×0+1"-" 6"|" )/√(3^2+1^2 )=√10/2,所以半弦长为("|" AB"|" )/2=√(r^2 "-" d^2 )=√("(" √5 ")" ^2 "-" (√10/2) ^2 )=√10/2,所以弦长|AB|=√10.
2015年中考真题精品解析 语文 （山东济南卷） 精编word版（原卷版）
⑦在仰韶文化时期，我国就有了对竹利用的确切记载。竹自竹简、珠笔到竹纸，在保存和传播我们中华民族的古老文化上立下了汗马功劳。以竹为题材的诗词歌赋，用竹编织和雕刻的艺术品，竹制的笙管笛箫奏出的音乐，无不给人类美的享受。⑧在我国文化史上，竹蕴含着中华民族重要的精神价值。人们在长期的劳动实践和文化活动中，把竹的生物特征逐渐升华为一种做人的美德。竹四季常青，不畏逆境，和松、梅并誉为“岁寒三友”；竹中空外直，虚怀若谷，和梅、兰、菊并称为“四君子”。⑨无论是魏晋嵇康、向秀等“竹林七贤”，还是唐朝李白、韩准等“竹溪六逸”，莫不对竹有一份执着和憧憬，清代郑板桥，与竹为邻，以竹为友，爱竹、写竹、画竹、赞竹。“千磨万击还坚韧，任尔东西南北风”，正是他坚忍不拔、超凡脱俗的人格写照。
2015年中考真题精品解析 语文（黑龙江大庆卷）精编word版（原卷版）
①2014年年中，世界卫生组织（WHO）公布了《2013年全球气候状况报告》。报告显示，2013年全球陆地和海洋表面平均温度为14．5℃，比1961-1990年的平均温度升高0．5℃。自有温度记录以来，全球14个最热年份中有13个出现在本世纪，而过去30年中每个10年都比前十年更热。②厄尔尼诺是发生在热带太平洋上海温异常增暖的气候现象，大范围热带太平洋增暖会造成全球气候变化。进入20世纪70年代后，全球出现的异常天气，都有范围广、灾情重、时间长等特点，而在这一系列异常天气的背后，厄尔尼诺暖流都起着重要作用。
2016年中考真题精品解析 语文（山东济南卷）精编word版（原卷版）
青蒿素治疗疟疾效果显著，是抵抗疟疾耐药性最好的药物。中国发现青蒿素时，美国也研制出一种抗疟新药—化学合成的甲氟喹，但疟原虫很快就适应了它，产生耐药性，临床使用后患者还出现了明显的不良反应。而对于青蒿素这种从中草药中提取的药物，疟原虫对它完全没有抵抗能力。1976 年1月，柬埔寨爆发疟疾，因疟原虫已经产生耐药性，疫情一时难以控制。中国医疗队携带一批青蒿素在柬埔寨大显神威，挽救了一大批疟疾患者的生命。
人教版高中数学选择性必修二导数的概念及其几何意义教学设计
新知探究前面我们研究了两类变化率问题：一类是物理学中的问题，涉及平均速度和瞬时速度；另一类是几何学中的问题，涉及割线斜率和切线斜率。这两类问题来自不同的学科领域，但在解决问题时，都采用了由“平均变化率”逼近“瞬时变化率”的思想方法；问题的答案也是一样的表示形式。下面我们用上述思想方法研究更一般的问题。探究1： 对于函数y=f(x) ，设自变量x从x_0变化到x_0+ ?x ，相应地，函数值y就从f(x_0)变化到f(〖x+x〗_0) 。这时， x的变化量为?x，y的变化量为?y=f(x_0+?x)-f(x_0)我们把比值?y/?x，即?y/?x=(f(x_0+?x)-f(x_0)" " )/?x叫做函数从x_0到x_0+?x的平均变化率。1．导数的概念如果当Δx→0时，平均变化率ΔyΔx无限趋近于一个确定的值，即ΔyΔx有极限，则称y＝f (x)在x＝x0处____，并把这个________叫做y＝f (x)在x＝x0处的导数(也称为__________)，记作f ′(x0)或________，即
人教版高中语文必修2《成语：中华文化的微缩景观》说课稿2篇
（三）教学目标1、明确成语的来源，了解成语的结构特点。2、学习积累成语的方法。3、梳理学习过的成语，做到能正确理解、使用所学的常用成语。（四）教学重点和难点1、学习积累成语的方法。2、正确理解、使用所学的常用成语。二、说教法新的《高中语文课程标准》要求学生主动去发现问题、解决问题，教师是课堂学习的组织者、参与者，是课堂的主导，而不是课堂的主体。而且，新的课程标准要求学生“能围绕所选择的目标加强语文积累，在积累的过程中，注重梳理”。在这种前提下，本节课可以采取以下方法：由于这种梳理是对学生已有的知识进行归纳分类，可能显得比较枯燥。为了避免这种枯燥感，可以采取设置情境和分组竞答的方法，调动学生的积极性。
新人教版高中英语必修3Unit 4 Space Exploration-Listening&Speaking&Talking教学设计一
Listening and Speaking introduces the topic of “talking about how to become an astronaut”. This period is aimed to inform students some details about the requirements of being an astronaut. Students can be motivated and inspired by the astronauts. Teachers ought to encourage students to learn from them and let them aim high and dream big.Listening and Talking introduces the theme of "talk about life in space". This part also informs students more details about life in space and can inspire students to be curious about this job. 1. Guide students to listen for numbers concerning dates, years and ages etc2. Cultivate students' ability to talk about how to become an astronaut and life in space ; 3. Instruct students to use functional sentences of the dialogue such as “ first of all, I am not sure, so what might be .. I guess.. I wonder…I am curious…)appropriately.1. Guide students to understand the content of listening texts in terms of the whole and key details; 2. Cultivate students' ability to guess the meaning of words in listening; discuss with their peers how to become a qualified astronaut and describe the life in space.Part 1: Listening and SpeakingStep 1: Lead inPredictionThe teacher can ask students to predict what the listening text is about by looking at the pictures.About how to become an astronaut./the requirements of an astronautStep 2: Then, play the radio which is about an interview a. And after finishing listening for the first time, the students need to solve the following tasks.
新人教版高中英语必修3Unit 4 Space Exploration-Discovering Useful Structure教学设计
The theme of the section is “Describe space facts and efforts to explore space”. Infinitives are one of non-finite verbs, as the subjects, objects, predicative, attributes and adverbials. This unit is about space exploration, which is a significant scientific activity, so every scientific activity has strong planning. Therefore, using the infinitives to show its purpose, explanations or restrictions is the best choice.1. Learn the structure, functions and features of infinitives.2. Learn to summarize some rules about infinitives to show purpose and modify.3. Learn to use infinitives in oral and writing English. 1. Learn the structure, functions and features of infinitives.2. Learn to summarize some rules about infinitives to show purpose and modify.3. Learn to use use infinitives in oral and writing English.Step 1 Lead in---Pair workLook at the following sentences and focus on the italicized infinitives. In pairs, discuss their functions. 1. I trained for a long time to fly airplanes as a fighter pilot..(作目的状语)2. As we all know, an astronaut needs to be healthy and calm in order to work in space..(作目的状语)3. First of all, you must be intelligent enough to get a related college degree..(作目的状语)4. Some scientist were determined to help humans realise their dream to explore space..(作定语)5. On 12 April 1961, Yuri Gagarin became the first person in the world to go into space..(作定语)Summary:1. 不定式的结构：to+do原形。2. 分析上面的句子，我们知道在描述太空探索时，动词不定式不仅可以用来表目的，还可以用来作定语，表修饰。
新人教版高中英语必修3Unit 4 Space Exploration-Listening&Speaking＆Talking教学设计二
The themes of this part are “Talk about how to become an astronaut” and “Talk about life in space”. As Neil Armstrong said “Mystery creates wonder and wonder is the basis of man’s desire to understand. Space is difficult for human to reach, therefore, humans are full of wonders about it. However, if wanting to achieve the dream of reaching the Moon, some of our human should work hard to be an astronaut at first. Part A(Talk about how to become an astronaut) is a radio interview in a radio studio, where the host asked the Chinese astronauts about his story how to become an astronaut. Yang Liwei told his dreamed to be an astronaut since childhood. Then he worked hard to get into college at 22. The next 10 years, he gradually became an experienced pilot. At the same time, to be an astronaut, he had to study hard English, science and astronomy and trained hard to keep in good physical and mental health and to practise using space equipment. Part B (Talk about life in space) is also an interview with the astronaut Brown, who is back on the earth. The host Max asked about his space life, such as his emotion about going back the earth, the eating, shower, brushing, hobbies and his work. Part A and Part B are interviews. So expressing curiosity about the guests’ past life is a communicative skill, which students should be guided to learn.1. Students can get detailed information about how Yang Liwei became an astronaut and Max’s space life.2. Students learn to proper listening strategy to get detailed information---listening for numbers and taking notes.3. Students can learn related sentences or phrases to express their curiosity like “ I wish to know...” “I’d love to know...”4. Students can learn more about the space and astronauts, even be interested in working hard to be an astronaut
新人教版高中英语必修3Unit 4 Space Exploration-Reading and Thinking教学设计一
Q4: What is the function of the International exploration ?Having astronauts from different countries on boardQ5: What can you learn from Para 4 ?China has made great achievements in exploring spaceQ6: What is the attitude to the space exploration ?SupportiveStep 6 Post reading---RetellPeople have always wanted to learn more about space. Before the mid-20th century, most people felt (1)_________ (travel) into space was an impossible dream. However, (2)____ the help of scientists, peoplesucceeded in realizing their dream (3) _________ (explore) space. On 4 October 1957, the Sputnik 1 satellite (4) ____________(launch) by the USSR. (5) ________________ scientists try to make sure nothing goes wrong, accidents can still happen. These disasters made everyone(6)___________(disappoint), but people still believe in the importance of (7) ________(carry) on space exploration. In 2003, China became the third country to (8)_____________ (independent) send humans into space. Then Shenzhou 6 and 7 completed (9)____ second manned orbit and the first Chinese spacewalk. In spite of the difficulties, scientists hope future (10)__________ (discovery) will not only enable us to understand the universe but also help us survive well into the future.Answers: 1. travelling 2. with 3. to explore 4. was launched 5. Although6. disappointed 7. carrying 8. independently 9. a 10. discoveriesStep 6 Post reading---Critical thinkingQ1: What do you think of the space exploration ? I think it is beneficial to us. Through further study of space, people will make full use of it in the future, such as the space experiments by Wang Yaping in Tian Gong 1.Q2: If you are determined to be an astronaut, what should you prepare at present ?First of all, I should study hard to get a related college degree. Besides, I must keep mental and physical healthy.Step 7. HomeworkTry to summarize the structure of the article by a mind map.
新人教版高中英语必修3Unit 4 Space Exploration-Reading and Thinking教学设计二
The theme of this unit focuses on “space exploration.” Students will learn about the training and experience needed to become an astronaut. The text is mainly about the development of space exploration. On the one hand, the text helps students to have a good understanding about the great feats humans have achieved, on the other hand, they will further understand the contributions that we Chinese have achieved, and feel confident and proud about our homeland and strengthen their love for our country. The teacher should instruct students to aim high and study harder to make great progress in the space career if possible.1. Read about the development and value of space exploration.2. Explore the mysteries of the universe and the achievements in space exploration.3. Skillfully use the vocabulary of this text to cultivate self-study ability 4. Develop cooperative learning ability through discussion.1. Enable the Ss to talk about the development and value of space exploration.2. Guide the Ss to summarize the main idea of each paragraph as well as the main idea of the text.3. Help Ss comprehend the main reasons for space exploration. Multi-media, textbook, notebooks.Step 1: Warming up and predictionLook at the title and the pictures of the text and predict what the text will be about?2. What are the main reasons for space exploration?
新人教版高中英语必修3Unit 4 Space Exploration-Reading for Writing教学设计二
⑦在我看来, 探索太空是值得的。As far as I am concerned, it is worthwhile to explore the space.Step 10 Writing---draftRecently, students in our class have had heated a discussion on whether space is worth exploring. Students hold different ideas about it.30% of us think space exploration is not worthwhile. They think space is too far away from us and our daily life and is a waste of money. And the money spent on space exploration can be used to solve the earth’s problems such as starvation and pollution.On the other hand，70% think space is worth exploring because we have benefited a lot from it，such as using satellites for communication and weather forecast. What’s more，with further space research，we may solve the population problem by moving to other planets one day. Also，space research will enable us to find new sources to solve the problem of energy shortages on the earth.As far as I am concerned, it is worthwhile to explore the space. Not only can it promote the development of society but also enrich our life. Step 11 Pair workExchange drafts with a partner. Use this checklist to help your partner revise his/her draft.1.Does the writer explain why he/she changed/wanted to change?2.Does the writer tell how the changes have improved or will improve his/her life?3.Is the text well－organised?4.Does the writer use words and expressions to show similarities and differences?5.Are there any grammar or spelling errors?6.Does the writer use correct punctuation？
新人教版高中英语必修3Unit 4 Space Exploration-Reading For Writing教学设计一
另一方面，其余的人反对这个计划，因为它可能会导致一些不好的影响。7.I hold the belief that space exploration not only enable us to understand how the universe began but also help us survived well into the future.我坚信探索太空不仅能够使我们了解宇宙的起源而且能够帮助我们更好地走进未来。8.I think we should spend more time and money exploring space so as to provide new and better solutions to people's shortterm and longterm problems.为了给人类的短期和长期问题提供更新和更好的解决方法，我认为我们应该花更多的时间和金钱来探索太空。9．From my point of view，it is wrong of young people to depend on their telephones too much，which may do harm to both their physical and mental health.在我看来，年轻人过度依赖手机是不对的，因为它们可能会对他们的身心健康都有害。最近你班同学就“人类是否应该进行宇宙探索”这个问题进行了激烈的讨论。有人认为，探索宇宙不仅让人类更好地了解宇宙的发展，还可以用来指导农业生产，以及把一些探索太空的高新技术用于现实生活；也有一些人认为探索太空花掉了大量的人力物力；影响了人们的生活水平。请你根据以下情况写一篇报告并发表自己的观点。注意：1.写作内容应包括以上全部要点，可适当发挥，使上下文连贯；
人教版新课标高中物理必修2探究弹性势能的表达式说课稿4篇
设疑自探：一个压缩或拉伸的弹簧就是一个“储能器”，怎样衡量形变弹簧蕴含能量的多少呢？弹簧的弹性势能的表达式可能与那几个物理量有关？类比：物体的重力势能与物体所受的重力和高度有关。那么弹簧的弹性势能可能与所受弹力的大小和在弹力方向上的位置变化有关，而由F=kl知弹簧所受弹力等于弹簧的劲度系数与形变量的乘积。预测：弹簧的弹性势能与弹簧的劲度系数和形变量有关。学生讨论如何设计实验： ①、用同一根弹簧在几次被压缩量不同时释放（劲度系数相同，改变形变量），观察小车被弹开的情况。②、分别用两根弹簧在被压缩量相同时释放（形变量相同，劲度系数不同），观察小车被弹开的情况。交流探究结果：弹性势能随弹簧形变量增大而增大。随弹簧的劲度系数的增大而增大。
人教版高中生物必修2减数分裂和受精作用说课稿
一 减数分裂高一生物减数分裂说课稿各位评委、老师：大家好，我今天说课的题目是高中生物必修2第二章第一节〈〈减数分裂与受精作用〉〉第一部分减数分裂第一课时精子形成过程。接下来我就从以下几个方面来说说这一节课。一、说教材1．教材地位和作用《减数分裂》这一部分内容不仅是第二章的重点内容，也是整本书的重点内容之一。它以必修一学过的细胞学知识、染色体知识、有丝分裂知识和初中生殖种类知识为基础。通过学习，使学生全面认识细胞分裂的种类、实质和意义，为后面学习遗传和变异，生物的进化奠定细胞学基础。2．教学目标（1）知识目标：掌握减数分裂的概念和精子的形成过程；理解减数分裂和受精作用的意义。（2）能力目标：通过观察减数分裂过程中染色体的行为变化，培养学生识图、绘图能力以及比较分析和归纳总结的能力。
人教版高中地理必修3荒漠化的防治—以我国西北地区为例说课稿
（设计意图： 通过这两个问题探究的形式可以了解学生对二、干旱为主的自然特征这一知识点的掌握情况，随堂练习有利于巩固强化学生的条例性知识。）三、荒漠化的成因1、自然因素：干旱、气候异常2、人为因素：（是荒漠化发生、发展的决定因素）自然原因启发学生利用已经学过的知识（干旱为主的自然特征）和给出的PPT资料来进行分析。人为原因以其危害结果用图表和图片的形式展示，使学生认识到人为因素是导致荒漠化最主要的因素。（设计意图：通过分析自然因素提供学生分析一区域环境建设的自然基础条件，而这也是较难的一点，再者，通过分析人为原因，是学生树立区域生态环境保护意识。）四、布置作业：书本课本20—22的活动—— 非洲萨赫勒地区荒漠化的自然、社会经济
新人教版高中英语必修3Unit 5 The Value of Money-Discovering Useful Structures导学案
4．They were going to find someone to take part in their bet when they saw Henry walking on the street outside.[归纳]1．过去将来时的基本构成和用法过去将来时由“would＋动词原形”构成，主要表示从过去某一时间来看将要发生的动作(尤其用于宾语从句中)，还可以表示过去的动作习惯或倾向。Jeff knew he would be tired the next day.He promised that he would not open the letter until 2 o'clock.She said that she wouldn't do that again.2．表示过去将来时的其他表达法(1)was/were going to＋动词原形：该结构有两个主要用法，一是表示过去的打算，二是表示在过去看来有迹象表明将要发生某事。I thought it was going to rain.(2)was/were to＋动词原形：主要表示过去按计划或安排要做的事情。She said she was to get married next month.(3)was/were about to＋动词原形：表示在过去看来即将要发生的动作，由于本身已含有“即将”的意味，所以不再与表示具体的将来时间状语连用。I was about to go to bed when the phone rang.(4)was/were＋现在分词：表示在过去看来即将发生的动作，通常可用于该结构中的动词是come，go，leave，arrive，begin，start，stop，close，open，die，join，borrow，buy等瞬间动词。Jack said he was leaving tomorrow.
学生个人两红两优表彰大会心得精品例文
随着自己的不断长大，发现我们身上的责任也越来越大，因为我们是新时代的青年，我们要做好自己的责任，要努力学习。都说我们是垮掉的一代，实际上并不是，我们是抗疫的主力军，冲在最前面为国家人民保驾护航！ 共青团建团百年作为新时代的的青年，我们要树立爱国主义精神，国家的前途，民族的命运，人民的幸福，是当代中国青年必须和必将承担的重任。 以便以后为国家和人民献上自己的一份力，在不远的将来我们国家会越来越好，中华民族屹立于世界民族之林，实现中华民族伟大复兴。
护士节护士长精品发言稿
这也就是我在护理岗位上不断提高，取得一点成绩的动力源泉。付出就会有回报，由于平时不懈的努力，在20_年度由甘肃省总工会、共青团甘肃省委、甘肃省人事厅、甘肃省卫生厅联合举办的甘肃省青年岗位技能大赛中夺取了甘肃省青年岗位能手护理技能比赛第一名的佳绩，并荣膺了“甘肃省杰出青年岗位能手”殊荣;同时，被省卫生厅推荐为全国卫生系统护理专业“巾帼建功”标兵和“全国青年岗位能手”。当然，这些成绩的取得，除了我个人的努力之外，离不开我院院领导的支持和鼓励，离不开同事们的关心和帮忙，借此机会，向他们表示最衷心的感激!
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本节课选自《普通高中课程标准数学教科书-必修一》（人 教A版）第五章《三角函数》，本节课是第1课时，本节主要介绍推广角的概念,引入正角、负角、零角的定义，象限角的概念以及终边相同的角的表示法。树立运动变化的观点,并由此进一步理解推广后的角的概念。教学方法可以选用讨论法,通过实际问题，如时针与分针、体操等等都能形成角的流念,给学生以直观的印象,形成正角、负角、零角的概念,明确规定角的概念，通过具体问题让学生从不同角度理解终边相同的角,从特殊到一般归纳出终边相同的角的表示方法。A.了解任意角的概念；B.掌握正角、负角、零角及象限角的定义，理解任意角的概念；C.掌握终边相同的角的表示方法；D.会判断角所在的象限。 1.数学抽象：角的概念；2.逻辑推理：象限角的表示；3.数学运算：判断角所在象限；4.直观想象：从特殊到一般的数学思想方法；