3 平行线的判定 教学设计.doc

1、measures planned implementation of technical protection measures and security schemes, the problems should be promptly reported to the Manager. 37th: carbon supervisor leadership and head of the company should periodically check the anti-accident measures planned, security technology protection meas

2、ures planned in implementation of measures against accidents and guarantee schemes, security technology protection measures planned in implementation. Seventh article 38th of education and training: new factory (company) production staff (including internships, commissioned officer), must be approve

3、d by the factory (company), workshop and team level safety education upon passing the examination before entering production site. Tertiary-level education after card registration, by the companys production technology section recovery archive, and reported to the company trade unions, safety record

4、. Training and examinations including the safe work procedures as well as relevant safety regulations, work environment and jobs there are risk factors, preventive measures and emergency treatment, and so on. The 39th article: new producers must receive the following training and qualified posts: (a

5、) the operating personnel, scheduling, must pass through the field point, institutional learning, on-site training and classes practice; (B) the maintenance, including technical staff, must undergo maintenance, technical specifications for learning and class practice; (C) special operations personne

6、l, must pass the national professional training, after obtaining a special operations qualifications before they can post. 40th: on-the-job training of production personnel: (I) post production staff should regularly carry out targeted of technical questions and answers, an accident expected on site

7、 training and anti-accident; (B) from running post 1 month and above the main post on duty or leave transportation . Drive system and security studies, arranged by upper management or organization of the examination. The 42nd article: June of every year once regulatory and safety procedures of the c

8、ompany system of examinations, examination the failed again, still not eligible waiting list study. Article 43rd: every year in June the work ticket issuer, assignee, licensee of work training, after passing the examination, as a formal announcement are eligible to work as ticket issuer, head of ins

9、pection, work permits and the right to a separate high-pressure equipment list, and reported to the Management Department. Failing the exam may not serve as a two person, stop classes, examinations before they can post. 44th: for breach of discipline system caused the accident, a kind of disorder an

10、d attempted serious responsibility for the accident, in addition to the relevant provisions dealing with should also be tasked to learn about a point system, and after passing the exam, before they can post. Article 45th: units of the company using the security video, slide projector, television, co

11、mputer, multimedia, radio, Billboard, artifacts, photo exhibitions, as well as security knowledge exam, lectures, contests, and other forms of advocacy, popularize the knowledge of security technology, targeted, Visual training, enhancing workers safety awareness and self-protection ability. Article

12、 46 新课标第一网不用注册，免费下载！第七章 平行线的证明3平行线的判定一、学生知识状况分析w w w .x k b 1.c o m 学生技能基础：在学习本课之前，学生对平行线的判定已经比较熟悉，也有了初步的逻辑推理能力，对简单的证明步骤有较清楚的认识，这为今天的学习奠定了一个良好的基础 活动经验基础：在以往的几何学习中，学生对动手操作、猜想、说理、讨论等活动形式比较熟悉，本节课主要采取学生分组交流、讨论等学习方式，学生已经具备必要的基础二、教学任务分析在以前的几何学习中，主要是针对几何概念、运算以及几何的初步证明（说理），在学生的头脑中还没有形成一个比较系统的几

13、何证明体系，本节课安排为什么它们平行旨在让学生从简单的几何证明入手，逐步形成一个初步的、比较清晰的证明思路，为此，本课时的教学目标是： 1.熟练掌握平行线的判定公理及定理； 2.能对平行线的判定进行灵活运用，并把它们应用于几何证明中通过经历探索平行线的判定方法的过程，发展学生的逻辑推理能力，逐步掌握规范的推理论证格式 3.通过学生画图、讨论、推理等活动，给学生渗透化归思想和分类思想 三、教学过程分析本节课的设计分为四个环节：情景引入探索平行线判定方法的证明反馈练习反思与小结第一环节：情景引入活动内容：回顾两直线平行的判定方法师：前面我们探索过直线平行的条件大家来想一想：两条直线在什么情况下互相

14、平行呢？生1：在同一平面内，不相交的两条直线就叫做平行线生2：两条直线都和第三条直线平行，则这两条直线互相平行生3：同位角相等两直线平行；内错角相等两直线平行；同旁内角互补两直线平行师：很好这些判定方法都是我们经过观察、操作、推理、交流等活动得到的上节课我们谈到了要证实一个命题是真命题除公理、定义外，其他真命题都需要通过推理的方法证实我们知道：“在同一平面内，不相交的两条直线叫做平行线”是定义“两条直线被第三条直线所截，如果同位角相等，那么这两条直线平行”是公理那其他的三个真命题如何证实呢？这节课我们就来探讨活动目的： 回顾平行线的判定方法，为下一步顺利地引出新课埋下伏笔教学效果： 由于平行线

15、的判定方法是学生比较熟悉的知识，教师通过对话的形式，可以使学生很快地回忆起这些知识第二环节：探索平行线判定方法的证明活动内容： 证明：两条直线被第三条直线所截，如果同旁内角互补，那么这两条直线平行 师：这是一个文字证明题，需要先把命题的文字语言转化成几何图形和符号语言所以根据题意，可以把这个文字证明题转化为下列形式：如图，已知，1和2是直线a、b被直线c截出的同旁内角，且1与2互补，求证：ab 如何证明这个题呢？我们来分析分析师生分析：要证明直线a与b平行，可以想到应用平行线的判定公理来证明这时从图中可以知道：1与3是同位角，所以只需证明1=3，则a与b即平行因为从图中可知2与3组成一个平角，

16、即2+3=180,所以：3=1802又因为已知条件中有2与1互补，即：2+1=180,所以1=1802,因此由等量代换可以知道：1=3师：好下面我们来书写推理过程，大家口述，老师来书写（在书写的同时说明：符号“”读作“因为”，“”读作“所以”）x_k_b_1证明：1与2互补（已知） 1+2=180（互补定义）1=1802（等式的性质）3+2=180（平角定义）3=1802（等式的性质）1=3（等量代换）ab（同位角相等，两直线平行）这样我们经过推理的过程证明了一个命题是真命题，我们把这个真命题称为：直线平行的判定定理这一定理可简单地写成：同旁内角互补，两直线平行注意：（1）已给的公理，定义和已

17、经证明的定理以后都可以作为依据用来证明新定理（2）证明中的每一步推理都要有根据，不能“想当然”这些根据，可以是已知条件，也可以是定义、公理，已经学过的定理在初学证明时，要求把根据写在每一步推理后面的括号内 证明：内错角相等,两直线平行师：小明用下面的方法作出了平行线，你认为他的作法对吗？为什么？（见相关动画）生：我认为他的作法对他的作法可用上图来表示：CFE=45,BEF=45因为BEF与FEA组成一个平角，所以FEA=180BEF=18045=135而CFE与FEA是同旁内角且这两个角的和为180，因此可知：CDAB师：很好从图中可知：CFE与FEB是内错角因此可知：“内错角相等，两直线平行

18、”是真命题下面我们来用规范的语言书写这个真命题的证明过程师生分析：已知，1和2是直线a、b被直线c截出的内错角，且1=2求证：ab证明：1=2（已知） 1+3=180（平角定义）2+3=180（等量代换） 2与3互补（互补的定义）来源:学+科+网Z+X+X+Kab（同旁内角互补，两直线平行）这样我们就又得到了直线平行的另一个判定定理：内错角相等，两直线平行 借助“同位角相等，两直线平行”这一公理，你还能证明哪些熟悉的结论呢？生1：已知，如图，直线ac,bc求证：ab证明：ac,bc（已知）1=902=90（垂直的定义）1=2（等量代换）ba（同位角相等，两直线平行）生2：由此可以得到：“如果两

19、条直线都和第三条直线垂直，那么这两条直线平行”的结论师：同学们讨论得真棒下面我们通过练习来熟悉掌握直线平行的判定定理活动目的： 通过对学生熟悉的平行线判定的证明，使学生掌握平行线判定公理推导出的另两个判定定理，并逐步掌握规范的推理格式教学效果： 由于学生有了以前学习过的相关知识，对几何证明题的格式有所了解，今天的学习只不过是将原来的零散的知识点以及学生片面的认识进行归纳，学生的认识更提高一步第三环节：反馈练习活动内容： 课本第231页的随堂练习第一题活动目的： 巩固本节课所学知识，让教师能对学生的状况进行分析，以便调整前进教学效果： 由于此题只是简单地运用到平行线的判定的三个定理（公理），因此

20、，学生都能很快完成此题第四环节：学生反思与课堂小结活动内容： 新*课*标*第*一*网 这节课我们主要探讨了平行线的判定定理的证明同学们来归纳一下完成下表： 由角的大小关系来证两直线平行的方法，再一次体现了“数”与“形”的关系；而应用这些公理、定理时，必须能在图形中准确地识别出有关的角 注意：证明语言的规范化推理过程要有依据活动目的： 通过对平行线的判定定理的归纳，使学生的认识有进一步的升华，再一次体会证明格式的严谨，体会到数学的严密性教学效果： 学生充分认识到证明步骤的严密性，对平行线判定的三个定理有了更进一步的认识课后作业：课本第232页习题6.4第1，2，3题思考题：课本第

21、233页习题6.4第4题（给学有余力的同学做）四、教学反思平行线是众多平面图形与空间图形的基本构成要素之一，它主要借助角来研究两条直线之间的位置关系，即通过两条直线与第三条直线相交所成的角来判定两条直线平行与否，在教学中，要紧紧围绕这些角（同位角、内错角、同旁内角）与平行线之间的关系展开。学生初学证明时，对于证明中的每一步的因果关系很茫然，有的学生尽管头脑中对每一步的前因后果都比较清楚，但写出来的证明过程前后没有因果关系，这需要教师在学生刚接触证明题时，再三强调这一点。对于初学者而言，为了更好地掌握推理方法，要保证推理有根有据，上一步的因与下一步的果的因果关系明确，保证证明过程层次分明、条理清

22、楚。新课标第一网系列资料 regular issuance system of internal and external accident cases, organizational learning, analysis and discussion on a regular basis, and educate the persons concerned in a timely manner. 47th article: strengthening the safety of staff, establishing the concept of legalizat

23、ion of production safety, establish a people-oriented concept, three do no harm (dont hurt yourself, no harm to others, not to be hurt). 48th eighth day routine: pre-shift and post-shift monitor organizations, safety assist. Before class: succession (started), combined with shift operation and tasks

24、 for better risk analysis, arranged security account considerations. After class: summarizing comment on duty and the security situation, praise good deeds criticism ignored safety, illegal operations and other adverse phenomena, and completes the record. 49th: safety day event organized by the moni

25、tor, safety help, workshop leaders and checking activities. Classes (groups) or rotating a safety day event a week, activities to learn more about the superior file and the spirit of the meeting, informed of the accident, analysis of the company, workshop and fewer security incidents, as well as the

26、 typical illegal team, analysis of operation environment, there may be a risk factor for the main content. 50th: security analysis companies every quarter of a security analysis; shop at least once a month analysis, comprehensive analysis of production trends, sum up lessons learned from and the wea

27、kness in safety management, accident prevention measures in the study. Meeting was chaired by enterprise security responsibility, concerning the participation of Heads of Department, workshop. Formation meeting and made public. 51st: security check for carbon companys periodic and non-periodic safet

28、y checks should be carried out. Periodic inspection includes fall and spring security checks, security checks should be combined with spring or autumn season characteristics and accident law . 52nd: security analysis companies should all be actively involved in the preparation of security advisories

29、, bulletins, integrated security, analysis of accident law, drawing on lessons learned from. 53rd: the companys safety safety month activities each year according to the Governments requirements and deployment of the group, safety month activities focus on advocacy efforts to improve production safety and strengt