对称轴的画法
3月31轴对称图形画法
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探究新知
说一说:你是如何根据对称轴,补全下面这个图形的?
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一“找”,找出图形 上每条线段的端点。
二“定”,根据对称 轴确定每一个端点的 对称点。 三“连”,依次连接 这些对称点,得到轴 对称图形的另一半。
课堂练习 根据对称轴画出图形的另一半。
课堂小结 这节课你们都学会了哪些知识?
轴对称图形中每组 对应点到对称轴的
B
距离相等。
A
2格 2格 B′ 每组对应点的连 线与对称轴垂直。
3格 3格 A′
课堂小结
这节课你们都学会了哪些知识?
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一“找”,找出图形 上每条线段的端点。
二“每定组”对应,点根的据连对称 轴确线定与每对一称轴个垂端直点。的 对称点。
三“连”,依次连接 这些对称点,得到轴 对称图形的另一半。
··· ··· ··· ···
课堂练习
画出下面这个轴对称图形的另一半。数学书83页做一做
B
·B′
A
D
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·C′
课堂练习
你能画出下面图形的另一半吗?试一试。
(1)
B′
A
B C
错 C′
课堂练习 你能画出下面图形的另一半吗?试一试。
数学书85页第6题
课堂练习
数学书84页第4题
根据对称轴,分别画出下面两个轴对称图形的另一半。
人教版五年级数学下册中知识点、易错点、易错题汇总
;4知识点易错点汇总★知识点归纳一、轴对称1、定义:把一个图形沿着某一条直线对折,如果它能够与另一个图形重合,那么就说这两个图形关于这条直线对称,这条直线叫做对称轴。
折叠后重合的点是对应点,叫做对称点。
2、性质:对称点到对称轴的距离相等。
3、轴对称图形:指具有特殊形状的一个图形,它可以有一条或多条对称轴。
二、旋转1、定义:把一个图形绕某一点(或轴)转动一定的角度的图形变换叫做旋转。
2、旋转三要素:旋转点(旋转中心)、旋转方向、旋转角度钟表中指针运动的方向为顺时针方向,与钟表中指针的运动方向相反的方向为逆时针方向。
3、性质:图形绕着某一点旋转一定的度数,图形的对应点、对应线段都旋转了相应的度数,对应点到旋转点的距离相等,对应的线段和对应的角度相等。
图形旋转后,形状、大小都没有发生变化,只有位置变了。
4、旋转90°的方法(1)找出原图行的关键点或关键线段;(2)借助三角板或量角器作原图行关键点或线段与旋转中心所在线段的垂线(3)在所垂线上量出或数出与原线段相等的长度(即找到原图关键点的对应点);(4)顺次连接所找到的对应点,即可得到原图形旋转90°后的图形。
5、时钟上包含12大格,60小格,时钟上相邻两数字间即为一大格,一大格为30°;每一大格又平均分为了五个小格,一小格为6°三、平移1、定义:指在一个平面内,将一个图形上的所有点都按照某个方向做相同距离的移动,这样的图形运动叫做图形的平移运动,简称平移。
2、性质:平移不改变图形的形状和大小。
3、图形平移的步骤:(1)确定原图形位置、平移的方向、平移的距离。
(2)找出原图形的各关键点。
(3)根据题目要求将各个点依次平移,找出各个点的对应点。
(4)顺次连接平移后的各点。
◆习题:1、图形的变换包括:、、。
其中只是改变原图形位置的变换是、。
2、如果一个图形沿着一条直线对折,两侧的图形能够完全重合,这样的图形就叫()图形,那条直线就是()。
二次函数图像画法与特性分析
二次函数图像画法与特性分析二次函数是高中数学中的重要内容之一,它在数学、物理、经济等领域都有广泛的应用。
本文将介绍二次函数图像的画法和特性分析。
一、二次函数图像的画法要画出二次函数的图像,首先需要确定函数的顶点和开口方向。
二次函数的一般形式为y = ax^2 + bx + c,其中a、b、c为常数。
根据a的正负可以判断二次函数的开口方向,当a>0时,开口向上;当a<0时,开口向下。
确定开口方向后,可以通过计算顶点的坐标来确定图像的位置。
二次函数的顶点坐标为(-b/2a, f(-b/2a)),其中f(x)为二次函数的值。
通过计算可以得到顶点坐标,然后将顶点标记在坐标轴上。
接下来,可以选择一些特殊点来确定图像的形状。
例如,可以选择x=0和x=1两个点来计算函数值,然后将这些点连接起来,就可以得到二次函数的大致形状。
二、二次函数图像的特性分析1. 对称轴:二次函数的图像关于对称轴对称。
对称轴的方程为x = -b/2a,通过计算可以得到对称轴的位置。
2. 最值点:二次函数的最值点即为顶点,通过计算顶点的坐标可以得到最值点的位置。
当a>0时,最值点为最小值;当a<0时,最值点为最大值。
3. 零点:二次函数的零点即为函数与x轴的交点。
通过求解二次方程ax^2 + bx + c = 0,可以得到零点的位置。
当判别式b^2-4ac>0时,函数有两个不同的零点;当判别式b^2-4ac=0时,函数有一个重根;当判别式b^2-4ac<0时,函数无实数根。
4. 函数的增减性:当a>0时,二次函数是上升的;当a<0时,二次函数是下降的。
通过计算函数的导数可以得到函数的增减性。
5. 函数的凹凸性:当a>0时,二次函数是凹的;当a<0时,二次函数是凸的。
通过计算函数的二阶导数可以得到函数的凹凸性。
通过对二次函数图像的特性进行分析,可以更好地理解函数的性质和变化规律。
部编数学八年级上册专题07轴对称及轴对称图形画法问题(解析版)含答案
2023--2024学年度人教版数学八年级上册期末复习核心考点三种题型精炼专题07 轴对称及轴对称图形画法问题一、选择题1.(2023深圳)下列图形中,为轴对称的图形的是()A. B. C. D.【答案】D【解析】根据轴对称图形的概念对各选项分析判断即可得解.A、不是轴对称图形,故本选项不符合题意;B、不是轴对称图形,故本选项不符合题意;C、不是轴对称图形,故本选项不符合题意;D、是轴对称图形,故本选项符合题意.故选:D.【点睛】本题主要考查了轴对称图形,解决问题的关键是熟练掌握轴对称图形的概念,轴对称图形概念,一个图形沿着一条直线折叠,直线两旁的部分能够互相重合,这个图形就是轴对称图形.2. (2023广东省)下列出版社的商标图案中,是轴对称图形的为()A. B. C. D.【答案】A【解析】根据轴对称图形的概念:一个图形沿一条直线折叠,直线两旁部分能够完全重合的图形;由此问题可求解.符合轴对称图形的只有A选项,而B、C、D选项找不到一条直线能使直线两旁部分能够完全重合;故选A.【点睛】本题主要考查轴对称图形的识别,熟练掌握轴对称图形的概念是解题的关键.3. (2023湖南湘潭)中国的汉字既象形又表意,不但其形美观,而且寓意深刻,观察下列汉字,其中是轴对称图形的是()A. 爱B. 我C. 中D. 华【答案】C【解析】根据轴对称图形的定义逐项判断即可.将选项A,B,D中的汉字沿某直线折叠后不能与本身重合,所以不符合题意;将图C中的汉字沿过中心的竖直方向的直线折叠直线两旁的部分能够重合,所以符合题意.故选:C.【点睛】本题主要考查了轴对称图形的判断,掌握定义是解题的关键.即将一个图形沿某直线折叠,直线两旁的部分能够重合,这样的图形是轴对称图形.4.(2023江苏连云港)在美术字中,有些汉字可以看成是轴对称图形.下列汉字中,是轴对称图形的是()A. B. C. D.【答案】C【解析】根据轴对称图形的概念逐项分析判断即可,轴对称图形的概念:平面内,一个图形沿一条直线折叠,直线两旁的部分能够完全重合的图形.【详解】选项A、B、D均不能找到这样的一条直线,使直线两旁的部分能够完全重合的图形,所以不是轴对称图形;选项C能找到这样的一条直线,使直线两旁的部分能够完全重合的图形,所以是轴对称图形;故选:C.【点睛】本题考查了轴对称图形的概念,轴对称图形的关键是寻找对称轴,图形两部分折叠后可重合.5.下列图案中,是轴对称图形的是()A. B. C. D.【答案】A【解析】根据轴对称图形的概念逐项分析判断即可,轴对称图形的概念:平面内,一个图形沿一条直线折叠,直线两旁的部分能够完全重合的图形.A.是轴对称图形,故该选项正确,符合题意;B.不是轴对称图形,故该选项不正确,不符合题意;C.不是轴对称图形,故该选项不正确,不符合题意;D.不是轴对称图形,故该选项不正确,不符合题意;故选A【点睛】本题考查了轴对称图形的概念,轴对称图形的关键是寻找对称轴,图形两部分折叠后可重合.6. 下列图形中,对称轴最多是( )A. 等边三角形 B. 矩形C. 正方形D. 圆【答案】D【解析】因为等边三角形有三条对称轴;矩形有两条对称轴;正方形有四条对称轴;圆有无数条对称轴.一般地,正多边形的对称轴的条数等于边数.故选D.7. (2023山东聊城)如图,在直角坐标系中,ABC V 各点坐标分别为()2,1A -,()1,3B -,()4,4C -.先作ABC V 关于x 轴成轴对称的111A B C △,再把111A B C △平移后得到222A B C △.若()22,1B ,则点2A 坐标为( )A. ()1,5B. ()1,3C. ()5,3D. ()5,5【答案】B【解析】三点()2,1A -,()1,3B -,()4,4C -的对称点坐标为()12,1A --,()11,3B --,()4,4C --,结合()22,1B ,得到平移规律为向右平移3个单位,向上平移4个单位,计算即可.【详解】∵三点()2,1A -,()1,3B -,()4,4C -的对称点坐标为()12,1A --,()11,3B --,()4,4C --,结合()22,1B ,∴得到平移规律为向右平移3个单位,向上平移4个单位,的故2A 坐标为()1,3.故选B .【点睛】本题考查了关于x 轴对称,平移规律,熟练掌握轴对称的特点和平移规律是解题的关键.8. 现实世界中,对称现象无处不在,中国的方块字中有些也具有对称性.下列汉字是轴对称图形的是( )A. B. C. D.【答案】D【解析】利用轴对称图形的概念可得答案.A .不是轴对称图形,故此选项不合题意;B .不是轴对称图形,故此选项不合题意;C .不是轴对称图形,故此选项不合题意;D .是轴对称图形,故此选项符合题意;故选:D .【点睛】本题主要考查了轴对称图形,关键是掌握如果一个图形沿一条直线折叠,直线两旁的部分能够互相重合,这个图形叫做轴对称图形.9.下列北京冬奥会运动标识图案是轴对称图形的是( )A. B. C. D.【答案】C【解析】根据轴对称图形的定义进行逐一判断即可.A.不是轴对称图形,故A 错误;B.不是轴对称图形,故B 错误;C.是轴对称图形,故C 正确;D.不是轴对称图形,故D 错误.故选:C .【点睛】本题主要考查了轴对称图形的定义,如果一个平面图形沿一条直线折叠,直线两旁的部分能够互相重合,这个图形就叫做轴对称图形.10.如图,△ABC 关于直线l 的对称图形是△DEF ,下列判断错误的是( )A. AB=DEB.BC ∥EFC.直线l ⊥BED.∠ABC=∠DEF 【答案】B【解析】轴对称图形的相关性质。
轴对称图形的性质及画法
配乐朗读。
小结
当一个人的身和他的内心相统一的时候,我们叫做“身心合一〞,而此时的纳兰性德,一生跟康熙皇帝出巡无数次,他早已厌倦了这样的征途,所以这种离别是不得不忍的离别,这种跋山涉水是不得不进行了山一程,水一程,这种听风沐雪也是他不得不的。那当他的身和心分开的时候,此时,纳兰性德的身在哪里?心在哪里?〔身在征途、心系故园〕
〔1〕先让学生用一张纸连续对折3次,再画出一个简单图形,剪出一个图案来,并在小组中互相说一说:剪出的是什么图案?是怎样剪出来的?
〔2〕让学生按照教材上的要求,动手折一折,画一画,剪一剪,再互相交流。
3.动手画一画,完成练习二十第4题,分别画出下面两个轴对称图形的另一半。
4.拓展题,教材85页第6题,试着画一画稍复杂的轴对称图形的另一半。
学生空间想象能力较弱:四年级学生的思维主要以形象思维为主,空间想象,几何直观能力较弱,在对称轴不是水平或竖直的情况下就容易找错对称点。
难点教学方法
1.通过直观的观察、思考、理解轴对称图形的性质。
2.通过课件演示在方格纸上画轴对称图形另一半的方法。
教学环节
教学过程
导入
引导学生观察图案,在小组中交流自己的发现。学生可能会发现这些都是轴对称图形。画出它们的对称轴
教学环节
教学过程
导入
1.如果用一个词表达你读完这首词的感受,你想到了哪个词?
〔艰难、悲壮、思乡、危险、豪迈、思念〕
2.指名学生朗读〔读出自己体会〕
知识讲解
〔难点突破〕
3.理解诗句。
〔1〕从哪一句词中读出了这种感受?
“山一程,水一程,身向榆关那畔行,夜深千帐灯。〞
《轴对称图形》说课稿北师大版数学三级下册
北师大版数学三年级下册《轴对称图形》说课稿一、教材分析1.教材的地位与作用《轴对称图形》是北师大版三年级下册第二单元《对称、平移和旋转》中第一课时的教案内容。
本节课是在认识常见立体图形和平面图形的基础上学习的。
对称是一种最基本的图形变换,对于帮助学生建立空间观念,培养学生空间想象力有着重要的作用。
轴对称图形的学习为今后学习平移、旋转、图形变换等知识打好基础。
所以,本课不仅为学生做好知识铺垫,也做好能力的过渡。
2. 教案目标根据“新课标”要求和教材的内容,本节课确定如下教案目标:(1)知识与技能感知现实生活中普遍存在的轴对称现象,体会轴对称图形特征,能够准确判断哪些图形是轴对称图形并找出对称轴,能够在方格纸上画出简单的轴对称图形。
(2)过程与方法通过图形分类、折纸、画图、剪纸等操作活动来认识和制作轴对称图形,体会数学分类思想和对应思想,从而运用轴对称图形的知识来解决实际问题。
(3)情感、态度与价值观发展学生的空间观念,培养学生热爱美、创造美的意识。
3、教案重难点由于教材并没有给出轴对称图形准确的定义,主要是通过直观演示,动手操作使学生感知并了解轴对称图形的基本特征,因此“初步认识轴对称图形的特征”就成为本节课的教案重点;在图形对称轴的判断和画图中,依靠是感知概念与特征来完成,因此“判断轴对称图形和掌握画轴对称图形的方法”是本节课的难点。
重点:认识轴对称图形特征。
难点:能正确判断和画出简单的轴对称图形。
二、学情分析学生年龄小,好动,好奇,思维活跃,并具有一定的数学思考能力。
感性认识强于理性认识,形象而直观的教案容易被他们接受。
三、教案方法分析如何更好地突出重点,突破难点,完成上述教案目标呢?根据教材与学生的特点教法分析:本节课我将采用多媒体辅助教案,加以引导、直观演示。
以独立思考、探究合作、交流与展示、竞赛活动为主要方式进行教案。
激发学生学习的积极性,让学生主动参与学习的全过程。
学法分析:我力争营造一个民主、平等、和谐、愉悦的学习气氛,充分发挥学生的主体性,通过学生初步观察、动手折纸、画图、剪纸等学习活动,用自己的思维方式主动探究,发现特征,学以致用。
五年级上册数学教案-2.2 轴对称再认识(二)|北师大版 (7)【精品】
五年上《轴对称再认识(二)》教学设计1、教学内容:新北师大版小学数学五年上第二单元《轴对称和平移》的第二节《轴对称再认识(二)》2、教材分析(1)教材内容的结构特点《轴对称再认识(二)》是北师大版小学数学五年级上册第二单元的教学内容,学生在第一学段已初步感知生活中的对称,初步认识了轴对称图形,为本单元的学习奠定了知识基础和经验基础。
关于这部分知识,要使学生能识别轴对称图形,能在方格纸上画出轴对称图形的对称轴;能在方格纸上补全一个简单的轴对称图形及某个图形的轴对称图形。
(2)教学内容在教材中的地位和作用这部分内容主要是让学生能在方格纸上画或补全轴对称图形,,让学生在折纸、画图等活动中,学会利用找关键点的方法画轴对称图形,为后面学习平移、旋转设计图形等知识积累感性经验,发展学生空间观念。
3、学情分析(1)学生的认知基础在日常生活中,轴对称现象对于孩子说并不陌生,自然界中具有轴对称性质事物很多,学生已经有了一些感性认识;(2)学生的活动经验基础学生们对学过的一些平面图形所具有的轴对称特征有一定的了解,已经形成了初步的空间观念。
(3)学生学习新知遇到的困难不能准确利用轴对称图形的特征把轴对称图形补充完整,往往出现轴两侧图形的端点到轴的距离不等的现象。
4、教学目标(1)知识与技能(包括核心素养):借助方格纸,补全一个简单的轴对称图形,或画出某个图形的轴对称图形。
(2)过程与方法通过观察、比较、操作的活动,让学生进一步体会轴对称图形的特征,积累图形运动的思维经验,发展空间观念。
(3)情感态度与价值观:激发学生对数学的兴趣,感受轴对称图形与生活的联系,培养数学的应用意识。
5、教学重点、难点(1)教学重点:能在方格纸上按要求画出轴对称图形的另一半,画出一个图形的轴对称图形。
教学难点:经历画图的过程,掌握画图的方法。
6、教学方法(体现出个性化的教学)鉴于教材特点和学生模仿能力强,思维信赖于具体直观形象的特点,我选用的是引导发现教学法,充分运用电教媒体,在演示、操作、观察、练习等师生的共同活动引导学生,让每个学生都动手、动口、动脑积极思维,进行“创造性”的学习,另外,在教学中我还注意利用图片的不同颜色的对比启发学生,运用iPad和PPT提高教学效率,动态演出直观生动的教学图片,激发学生的学习兴趣,培养应用意识。
《画轴对称图形---对称图形的画法》1
五亩一中八年级数学学科电子教案设计主备教师:王英佩副备教师:月日(英文版)Two regulations promulgated for implementation is in the party in power for a long time and the rule of law conditions, the implementation of comprehensive strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting each other, the < code > adhere to a positive advocate, focusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; < rule > around the party discipline, disciplinary ruler requirements, listed as "negative list, focusing on vertical gauge, draw the party organizations and Party members do not touch the" bottom line ". Here, the main from four square face two party rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third part introduces two party regulations modified the main changes and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the party. < code > and < Regulations > revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members and leading cadres honest politics several guidelines > and < Chinese Communist Party discipline and Punishment Regulations > column 1 by 2015 to strengthenparty laws and regulations focus. Two party regulations revision work lasted a Y ears, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for the wisdom of our predecessors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the party's leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the < code > and < rule >, reflects the party's 18 and the eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the party's eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of < the ICAC guidelines > in < in 1997 Leaders as members of the Communist Party of China clean politics certain criteria (Trial) > based on revised, the promulgation and implementation of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Content is too complicated, "eight prohibition, 52 are not allowed to" hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with the party discipline, disciplinary regulationsrepeat and Criminal law and other laws and regulations repeat; the fourth is to "clean" the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres above. < rule > is in 1997 < Chinese Communist Party disciplinary cases (Trial) > based on revision, in December 2003 the promulgation and implementation, to strengthen the construction of the party play very important role. Along with the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half of the provisions and criminal law and other countries laws and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibility to pursue; third is the main discipline for the leading cadres, does not cover all Party members. Based on the above situation, need to < the criterion of a clean and honest administration > and < rule > the two is likely to be more relevant regulations first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tree and call up the majority of Party members and cadres of the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general books recorded in the FifthPlenary Session of the eighth session of the Central Commission for Discipline Inspection, on the revised regulations < > made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regulations revision. The Standing Committee of the Central Commission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a forum will listen to part of the province (area) secretary of the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs DepartmentThe first party committee is mainly responsible for people, views of experts and scholars and grassroots party organizations and Party members. Approved by the Central Committee of the Communist Party of China, on 7 September 2015, the general office of the Central Committee of the Party issued a notice to solicit the provinces (autonomous regions, municipalities) Party, the central ministries and commissions, state ministries and commissions of the Party (party), the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Central Commission for Discipline Inspection of extensive solicitation of opinions, careful study, attracting, formed a revised sent reviewers. In October 8 and October 12, Central Committee PoliticalBureau Standing Committee and the Political Bureau of the Central Committee After consideration of the two regulations revised draft. On October 18, the Central Committee of the Communist Party of China formally issued two regulations. Can say, two laws amendment concentrated the wisdom of the whole party, embodies the party. Second, < code > and < Regulations > revision of the basic principles of two party regulations revision work and implement the party's eighteen, ten eight plenary, the spirit of the Fourth Plenary Session of the Eleventh Central Committee and General Secretary Xi Jinping important instructions on the revised < low political criterion > and < Regulations >, highlighting the ruling party characteristics, serious discipline, the discipline quite in front of the law, based on the current, a long-term, advance as a whole, with Bu Xiuding independent < rule > and < rule >. Main principle is: first, adhere to the party constitution to follow. The constitution about discipline and self-discipline required specific, awaken the party constitution of party compasses party consciousness, maintaining the authority of the constitution. General Secretary Xi Jinping pointed out that "no rules, no side round. Party constitution is the fundamental law, the party must follow the general rules. In early 2015 held the eighth session of the Central Commission for Discipline Inspection Fifth Plenary Session of the 16th Central Committee, Xi Jinping again pointed out that constitution is the party must follow the general rules, but also the general rules." the revisionof the < code > and < rule > is Method in adhere to the regulations established for the purpose of combining rule of virtue is to adhere to the party constitution as a fundamental to follow, the constitution authority set up, wake up the party constitution and party rules the sense of discipline, the party constitution about discipline and self-discipline specific requirements. 4 second is to adhere to in accordance with the regulations governing the party and the party. The Party of rule of virtue "de", mainly refers to the party's ideals and beliefs, excellent traditional style. The revised the < code > closely linked to the "self-discipline", insisting on the positive initiative, for all members, highlight the "vital few", emphasized self-discipline, focusing on the morality, and the majority of Party members and the ideological and moral standards. The revised < > Ji method separately, Ji, Ji Y an to Method, as a "negative list", emphasizing the heteronomy, focusing on vertical gauge. Is this one high and one low, a positive reaction, the strict party discipline and practice results transformation for the integration of the whole party to observe moral and discipline requirements, for the majority of Party members and cadres provides benchmarking and ruler. Third, insist on to. In view of the problems existing in the party at the present stage, the main problems of Party members and cadres in the aspect of self-discipline and abide by the discipline to make clearly defined, especially the party's eighteen years strict political discipline and political rules, organization and discipline andto implement the central eight provisions of the spirit against the four winds and other requirements into Disciplinary provisions. Not one pace reachs the designated position, focusing on in line with reality, pragmatic and effective. After the revision of major changes, major changes in the < code > and < rule > modified and needs to grasp several key problems (a) < code > < code > adhere to according to regulations governing the party and party with morals in combination, for at the present stage, the leadership of the party members and cadres and Party members in existing main problems of self-discipline, put forward principles, requirements and specifications, showing Communists noble moral pursuit, reflected at all times and in all over the world ethics from high from low 5 common requirements. One is closely linked to the "self-discipline", removal and no direct relation to the provisions of . the second is adhere to a positive advocate, "eight prohibition" 52 are not allowed to "about the content of the" negative list moved into synchronization amendment < cases >. Three is for all the party members, will apply object from the leadership of the party members and cadres to expand to all Party members, fully embodies the comprehensive strictly required. The fourth is prominent key minority, seize the leadership of the party members and cadres is the key, and put forward higher requirements than the ordinary Party members. Five is to simplify, and strive to achieve concise, easy to understand, easy to remember. The revised < code > is the ruling Party since the first insists ona positive advocate forAll Party members and the self-discipline norms, moral declaration issued to all members of the party and the National People's solemn commitment. > < criterion of a clean and honest administration consists of 4 parts, 18, more than 3600 words. After the revision of the < code >, a total of eight, 281 words, including lead, specification and Party member cadre clean fingered self-discipline norms, etc. Part 3 members low-cost clean and self-discipline, the main contents can be summarized as "four must" "eight code". Lead part, reiterated on ideal and faith, fundamental purpose, the fine traditions and work style, noble sentiments, such as "four must" the principle of requirements, strong tone of self-discipline, The higher request for 6 and supervised tenet, the foothold in permanent Bao the party's advanced nature and purity, to reflect the revised standards requirements. Members of self-discipline norms around the party members how to correctly treat and deal with the "public and private", "cheap and rot" thrifty and extravagance "bitter music", put forward the "four norms". Party leader cadre clean fingered self-discipline norms for the leadership of the party members and cadres of the "vital few", around the "clean politics", from civil servant of the color, the exercise of power, moral integrity, a good family tradition and other aspects of the leadership of the party members and cadres of the "four norms" < > < norm norm. "The Party member's self-discipline norms" and "party members and leading cadre clean fingered self-discipline norms," atotal of eight, collectively referred to as the "eight". "Four must" and "eight" of the content from the party constitution and Party's several generation of leaders, especially Xi Jinping, general secretary of the important discussion, refer to the "three discipline and eight points for attention" statements, and reference some embody the Chinese nation excellent traditional culture essence of epigrams. (2) the revised regulations, the main changes in the revised Regulations > to fully adapt to the strictly requirements, reflects the according to the regulations governing the law of recognition of deepening, the realization of the discipline construction and Jin Ju. < rule > is party a ruler, members of the basic line and follow. And the majority of Party members and cadres of Party organizations at all levels should adhere to the bottom line of thinking, fear discipline, hold the bottom line, as a preventive measure, to keep the party's advanced nature and purity. 1, respect for the constitution, refinement and discipline. Revised < rule > from comprehensive comb physical constitution began, the party constitution and other regulations of the Party of Party organizations and Party discipline requirements refinement, clearly defined in violation of the party constitution will be in accordance with regulations to give the corresponding disciplinary action. The original 10 categories of misconduct, integration specification for political discipline, discipline, honesty and discipline masses Ji Law and discipline and discipline and other six categories, the content of < rule >real return to Party discipline, for the majority of Party members and listed a "negative list. 7 2, highlighting the political discipline and political rules. > < Regulations according to the stage of the discipline of outstanding performance, emphasizing political discipline and political rules, organization and discipline, in opposition to the party's leadership and the party's basic theory, basic line, basic program and basic experience, the basic requirement of behavior made prescribed punishment, increase the cliques, against the organization such as violation of the provisions, to ensure that the central government decrees and the Party of centralized and unified. 3, adhere to strict discipline in the law and discipline In front, Ji separated. Revised < Regulations > adhere to the problem oriented, do Ji separated. Any national law existing content, will not repeat the provisions, the total removal of 79 and criminal law, repeat the content of the public security management punishment law, and other laws and regulations. In the general reiterated that party organizations and Party members must conscientiously accept the party's discipline, die van comply with national laws and regulations; at the same time, to investigate violations of Party members and even criminal behavior of Party discipline and responsibility, > < Regulations distinguish five different conditions, with special provisions were made provisions, so as to realize the connection of Party discipline and state law. 4, reflect Wind building and anti-corruption struggle of the latest achievements. < rule > the party's eighteen yearsimplement the spirit of the central provisions of the eight, against the requirements of the "four winds" and transformation for disciplinary provisions, reflecting the style construction is always on the road, not a gust of wind. In the fight against corruption out of new problems, increase the trading rights, the use of authority relatives profit and other disciplinary terms. Prominent discipline of the masses, the new against the interests of the masses and ignore the demands of the masses and other disciplinary terms and make provisions of the disposition and the destruction of the party's close ties with the masses.Discipline to protect the party's purpose. 8 of these regulations, a total of three series, Chapter 15, 178, more than 24000 words, after the revision of the regulations a total of 3 series, Chapter 11, 133, 17000 words, divided into "general" and "special provisions" and "Supplementary Provisions" Part 3. Among them, add, delete, modify the provisions of the proportion of up to nearly 90%. 1, the general general is divided into five chapters. The first chapter to the regulations of the guiding ideology, principles and scope of application of the provisions, highlight the strengthening of the party constitution consciousness, maintenance the authority of Party Constitution, increase the party organizations and Party members must abide by the party constitution, Y an Centralized centralized, would examine at all levels of the amended provisions implementing and maintaining Party discipline, and consciously accept the party discipline,exemplary compliance with national laws and regulations. The second chapter of discipline concept, disciplinary action types and effects of the regulations, will be a serious warning from the original a year for a year and a half; increase the Party Congress representative, by leaving the party above (including leave probation) punishment, the party organization should be terminated its representative qualification provisions. The third chapter of the disciplinary rules of use prescribed in the discipline rectifying process, non convergence, not close hand classified as severely or heavier punishment. "Discipline straighten "At least eighteen years of five years, these five years is to pay close attention to the provisions of the central eight implementation and anti -" four winds ". The fourth chapter on suspicion of illegal party disciplinary distinguish five different conditions, with special provisions were made provisions, to achieve effective convergence of Party and country 9 method. < rule > the provisions of Article 27, Party organizations in the disciplinary review found that party members have committed embezzlement, bribery, dereliction of duty dereliction of duty and other criminal law act is suspected of committing a crime shall give cancel party posts, probation or expelled from the party. The second is < Regulations > Article 28 the provisions of Party organizations in the disciplinary review But found that party members are stipulated in the criminal law, although not involved in a crime shall be investigated for Party discipline and responsibility shouldbe depending on the specific circumstances shall be given a warning until expelled punishment. This situation and a difference is that the former regulation behavior has been suspected of a crime, the feeling is quite strict, and the latter for the behavior not involving crime, only the objective performance of the provisions of the criminal code of behavior, but the plot is a crime to slightly. < Regulations > the 29 provisions, Party organizations in the discipline review found that party members and other illegal behavior, affect the party's image, the damage to the party, the state and the people's interests, we should depend on the situation Seriousness given disciplinary action. The loss of Party members, seriously damaging the party's image of behavior, should be given expelled from the party. At this article is party member is in violation of the criminal law outside the other illegal acts, such as violates the public security administration punishment law, customs law, financial laws and regulations behavior. The fourth is < cases > Article 32 stipulates, minor party members and the circumstances of the crime, the people's Procuratorate shall make a decision not to initiate a prosecution, or the people's court shall make a conviction and exempted from criminal punishment shall be given within the party is removed from his post, probation or expelled from the party. Party members and crime, sheets were fined in accordance with For acts; the principal Ordinance amended the provisions of the preceding paragraph. This is the new content, in order to achieve Ji method effectiveconvergence. Five is < > the thirty third article 10 of the provisions, the Party member due to an intentional crime is sentenced to criminal law (including probation) sheets or additional deprivation of political rights; due to negligence crime and was sentenced to three years or more (excluding three years) a penalty, shall give expelled punishment. Due to negligence crime is convicted and sentenced to three years (including three years) in prison or be sentenced to public surveillance, detention, shall in general be expelled from the party. For the individual may not be expelled from the party, should control Approval. This is followed and retained the original > < Regulations the provisions of punishment party authorization rules and report to a level party organizations. For is "party members with criminal acts, and by the criminal punishment, generally should be expelled from the party". The fifth chapter of probationary Party member of the discipline and discipline after missing members of the treatment and punishment decisions, such as the implementation of the provisions, clear the related party discipline and punishment decision made after, for duties, wages and other relevant alteration formalities for the longest time. 2, sub sub section will the original regulations of10 categories of acts of violation of discipline integration revised into 6 categories, respectively, in violation of the punishments for acts of political discipline "in violation of discipline behavior of punishment" in violation of integrity of disciplinary action points "of violation punishments for actsof mass discipline" "the violation of work discipline, punishment" in violation of discipline of life behavior punishment "6 chapters. 3, annex" Supplementary Provisions "clear authority making supplementary provisions of, cases of interpretative organ, as well as regulations implementation time and retroactivity etc.. 11 (3) learning understanding > < regulations needs to grasp several key problems The first problem -- about the violation of political discipline behavior > < new ordinance chapter 6 the political discipline column for the six disciplines, that is the main opposition to Party leadership and the opposition of the basic theory, basic line, basic program and basic experience, basic requirements of misconduct made provisions of the disposition, especially the eighteen since the CPC Central Committee put forward the Yan Mingzheng treatment of discipline and political rules requirements and practical achievements transformation for Discipline article, increase the false debate central policies, cliques, against the organization review, make no discipline of the principle of harmony terms. These are the party's eighteen years in comprehensive strictly Process combined with the practice of rich content. (1) false debate the central policies and undermine the Party of centralized and unified the problem is made in accordance with the provisions of the party constitution. Constitution in general programme requirements adhere to democratic centralism is one of the requirements of the construction of the party must adhere to the four cardinal. Applicationof this principle is not only the party the basic organization principle and is also the mass line in party life, it requires that we must fully develop inner-party democracy, respect for the dominant position of Party members, safeguarding the Party member democratic rights, give full play to the enthusiasm and creativity of the party organizations at all levels and Party members, at the same time, also must implement the right concentration, ensure the party's mission < the chaos in unity and concerted action to ensure that the party's decision to get quickly and effectively implementing. The Party Central Committee formulated the major principles and policies, through different channels and ways, fully listen to the party organizations and Party members of the opinions and suggestions, but 12 is some people face to face not to say back blather "" will not say, after the meeting said, "" Taiwan does not say, and nonsense ", in fact, not only disrupt the people thought, some causing serious consequences, the damage to the Party of the centralized and unified, hinder the central policy implementation, but also a serious violation of the democratic system of principles. There is no doubt that shall, in accordance with the Regulations > 4 Specified in Article 6 to give the appropriate punishment. For did not cause serious consequences, to give criticism and education or the corresponding tissue processing. (2) about the destruction of the party's unity < New Regulations > the forty eighth to fifty second article, to damage Party's unity unified and violation of political discipline, punishment situationmade explicit provisions. Article 52 of the new "in the party get round group, gangs seek private gain, cliques, cultivate private forces or through the exchange of interests, for their own to create momentum and other activities to gain political capital, given a serious warning or withdraw from their party posts disposition; if the circumstances are serious, to give Leave a party to observation or expelled from the party. (3) on against the organization review of the provisions of the constitution, party loyalty honesty is party members must comply with the obligations. Members must obey the organization decision, shall not violate the organization decided encounters by asking questions to find organization, rely on the organization, shall not deceive the organization, against the organization. For example, after the investigation does not take the initiative to explain the situation, but to engage in offensive and defensive alliance, hiding the stolen money is against survey organization, is a violation of the behavior of political discipline. Article 24 of the original > < Regulations, although the provisions of the interference, hinder group review the behavior of the fabric can be severely or 13 Aggravated punishment, but did not put this kind of behavior alone as a discipline for qualitative amount of discipline. > < new regulations increase the Article 57, "anti organization review, one of the following acts, given a warning or serious warning; if the circumstances are relatively serious, giving removed from or placed on probation within the party post; if the circumstances are serious, give。
一元二次函数图象的超简单画法
一元二次函数图象的超简单画法01首先画出直角坐标系。
02找点,首先找二次函数的顶点,根据所学知识易得,一元二次函数的对称轴为x=-b/2a,那么图中的函数对称轴就是x=1,计算出所得y 值,同时在函数中多找出几个位于对称轴附近的坐标点。
03根据上一步找出来的点在直角坐标系中描出来。
04然后用一段平滑的曲线将这些点全部连接起来就是我们的一元二次图像。
05上面只是通用的方法,对于某些比较特殊的一元二次函数,我们可以像下面这样更简单的作图。
首先观察函数右端是否可以变形,比如这里变形为y=(x-1)^2,那么函数的对称轴就可以直观的看出为x=1,顶点为(1,0)。
06然后按照之前同样的方式进行找点描点。
07再将各个黑点都用平滑的曲线连接起来,就构成了一元二次函数的抛物线。
08第三种作图方式也是我们常用的一种,首先根据公式x=-b/2a找出函数的对称轴,并计算出对应y值作为对应顶点。
09然后在对称轴的一侧找出另外的几个点并标出来。
10然后用平滑的曲线将对称轴一侧的点连接起来。
11最后将这一侧的曲线按对称轴对称描绘到另一侧即可构成完整的一元二次函数图像。
画对称轴的三种方法
画对称轴的三种方法对称轴是图形学中重要的概念之一,它指的是平面上一条直线,将图形沿着这条直线进行翻转后,两边的图形完全一样。
在绘画、制图、设计等领域,对称轴的运用十分广泛,因此学会如何准确地画出对称轴是非常必要的。
本文将介绍三种画对称轴的方法,希望能为读者提供帮助。
一、用工具画对称轴第一种方法是使用直尺和铅笔来画对称轴。
具体步骤如下:1.用直尺在图形中心位置画一条直线,这条直线必须经过图形的中心点。
2.用铅笔将这条直线延长,直到它超出图形的边缘。
3.将图形沿着这条直线进行翻转,如果两边的图形重合,则说明这条直线是对称轴。
4.用橡皮擦去多余的线条,保留对称轴即可。
这种方法简单易行,适合于对称轴较简单的图形。
二、用纸板画对称轴第二种方法是使用纸板来画对称轴。
具体步骤如下:1.将纸板对折,使两边完全重合。
2.将需要画对称轴的图形放在纸板的一侧,使它与纸板的折痕对齐。
3.用铅笔沿着图形的边缘,在纸板上画出图形的轮廓。
4.将纸板展开,将图形沿着纸板的折痕进行翻转,如果两边的图形重合,则说明这条折痕是对称轴。
5.用剪刀将纸板沿着对称轴剪开,保留对称轴即可。
这种方法适用于对称轴较复杂的图形,可以通过对纸板的折叠来快速确定对称轴的位置。
三、用数学方法画对称轴第三种方法是使用数学方法来画对称轴。
具体步骤如下:1.找到图形的中心点,可以通过计算或者直观感觉来确定。
2.找到图形上每一个点和中心点之间的连线。
3.将每一个点和中心点之间的连线进行翻转,得到一条新的线段。
4.将所有新的线段连接起来,得到一条直线,这条直线就是对称轴。
这种方法需要一定的数学基础,但是可以准确地画出对称轴,适用于对称轴的位置比较重要的情况。
总结以上是三种画对称轴的方法,它们分别是用工具画对称轴、用纸板画对称轴和用数学方法画对称轴。
不同的方法适用于不同的情况,读者可以根据自己的需要选择合适的方法。
在实际应用中,画出准确的对称轴可以帮助我们更好地完成绘画、制图、设计等任务,因此掌握这些方法是非常有用的。
北师大版五年级上册数学知识点归纳
北师大版五年级上册数学知识点归纳(总8页)--本页仅作为文档封面,使用时请直接删除即可----内页可以根据需求调整合适字体及大小--北师大版五年级数学上册知识点汇总第一单元小数除法1、除数是整数的小数除法计算法则:除数是整数的小数除法,按照整数除法的法则去除,商的小数点要和被除数的小数点对齐;如果除到被除数的末尾仍有余数,就在余数后面添0再继续除。
2、除数是小数的小数除法计算法则:除数是小数的除法,先移动除数的小数点,使它变成整数;除数的小数点向右移动几位,被除数的小数点也向右移动几位(位数不够的,在被除数末尾用0补足),然后按照除数是整数的小数除法进行计算。
3、在小数除法中的发现:①当除数大于1时,商小于被除数。
②当除数小于1时,商大于被除数。
4、小数除法的验算方法:①商×除数=被除数(通用)②被除数÷商=除数5、商的近似数:根据要求要保留的小数位数,决定商要除出几位小数,再根据“四舍五入”法保留一定的小数位数,求出商的近似数。
例如:要求保留一位小数的,商除到第二位小数可停下来;要求保留两位小数的,商除到第三位小数停下来……如此类推。
6、循环小数问题:A、小数部分的位数是有限的小数,叫做有限小数。
如,、等。
B、小数部分的位数是无限的小数,叫做无限小数。
如……等。
C、一个数的小数部分,从某位起,一个数字或者几个数字依次不断重复出现,这样的小数叫做循环小数。
(如………)D、一个循环小数的小数部分,依次不断重复的数字,叫做小数的循环节。
(如…的循环节是3,…的循环节是67,…的循环节是258)7、用简便方法写循环小数的方法:只写一个循环节,并在这个循环节的首位和末位上面记一个小圆点。
只有一个数字循环节的,就在这个数字上面记一个小圆点;有两位小数循环的,就在这两位数字上面,记上小圆点;有三位或以上小数循环的,在首位和末位记上小圆点。
8、除法中的变化规律:①商不变性质:被除数和除数同时扩大或缩小相同的倍数( 0除外),商不变。
人教2011版小学数学四年级图形的运动——轴对称
图形的运动——轴对称教学内容:人教版小学数学四年级下册第82页“轴对称”教材分析:小学阶段对“轴对称”的学习共安排了两次。
第一次在二年级下册,侧重于借助生活中的对称现象,整体感知轴对称图形。
第二次在四年级下册,侧重于认识轴对称是一种运动,认识它的特征,进而利用运动特征来画轴对称图形。
本节课是对“轴对称”的第二阶段的学习,是学生在初步认识轴对称图形的基础上,用“对称点到对称轴的距离”等定量刻画的方法来进一步分析图形的特点。
教材将方格背景和对称轴直接呈现,引导学生通过“数一数”,发现轴对称图形的特征。
然后基于此,学习“补全轴对称图形”的方法,更深刻地认识轴对称图形。
学生分析:在二年级的时候,学生已经有了对轴对称图形的直观认知,知道能对折重合的图形是轴对称图形,能够判断一个简单的图形是不是轴对称图形,这是学生已有的学习经验。
但是学生头脑中的轴对称是一个具有特殊性质的图案,是静止的,不能从运动的角度理解轴对称。
另外,在探究轴对称图形的特征时,对于对称点到对称轴的距离容易察觉,但是对称点连线与对称轴垂直这一隐形特征学生较难发现。
在画轴对称图形的另一半时,学生一般采用“对边”的方法,只有极少数孩子能想到“找点连线”的方法。
设计理念:1.从“轴对称图形”到“轴对称运动”“轴对称”有两种理解方式:一种是轴对称图形。
即具有对折重合特质的图案。
另一种是轴对称运动。
最直观的理解方式是“翻折”。
从某种意义上说:轴对称图形指的是运动的结果,侧重于空间认知,轴对称运动指的是运动的过程,更利于学生的空间想象。
因此,把轴对称理解为图形的运动方式才是本质。
第一阶段学习轴对称图形侧重于对图形的整体感知,是对轴对称第一种内涵的理解。
本节课,笔者试图从轴对称图形过渡到轴对称运动,对轴对称的内涵做进一步的拓展,体会轴对称也和平移旋转一样是图形的一种运动方式,使学生在图形的运动变化中理解轴对称现象,感悟轴对称运动的特征。
2.在运动中发现特征,掌握画法。
第七单元 第1课时 轴对称(教学课件)-四年级数学下册人教版
探究新知
presentation
轴对称图形画法并不难,找准关键点是关键。 点轴距离要按格算,才能找得准对称点。 依次连接各对称点,轴对称图形准确现。
学习任务四
达标练习,巩固成果
达标练习
practice
1. 说一说,轴对称图形有哪些特点? 答:轴对称图形沿着对称轴对折,两侧的图形能够完全重合;
课前导入
Lead
in
知识链接
knowledge link
观察这些物体,你能发现它们都有什么共同特征?
它们都是一类特殊的 图形——轴对称图形。
这些图案中蕴含着哪些 数学知识,今天我们来 了解更多轴对称的知识!
学习任务一
进一步认识轴对称图形及其 对称轴
探究新知
presentation
看一看、想一想:你发现了什么?
力,发展空间观念。
3 让学生在活动中欣赏图形的变换美,进一步感受 轴对称在生活中的应用,体会学习数学的价值。
02. 重点难点 Leaning points 学习重点 掌握轴对称图形的特征和性质。 学习难点 能在方格纸上画出轴对称图形的另一半。 核心素养 让学生经历“做”数学的过程,在操作中理解规 律,感受知识间的联系。
达标练习
practice
8.你能画出下面图形的另一半吗?试一试。
A′ A
B C
(1)找出图形中每条线段的端点,分 别命名为A、B、C、D。
其中A、D两个端点在对称轴上,分别 与其对称点位置重合。
D′ D
教材第82页“练习二十”第7题
达标练习
practice
8.你能画出下面图形的另一半吗?试一试。
第七单元图形的运动(二)操作题真题(培优卷)-四年级下册数学高频考点专项培优卷(人教版)
第七单元图形的运动(二)操作题真题(培优卷)四年级下册数学高频考点专项培优卷(人教版)1.(2020春•新野县期末)在下面方格处,写出2个具有对称性的汉字和数字.2.(2019秋•金牛区期末)如图所示剪下来的图形打开后是什么样子?画一画。
3.(2022秋•怀宁县期末)以虚线为对称轴,分别画出下列三角形的轴对称图形。
4.(2022秋•红谷滩区期末)在方格纸上设计一个轴对称图形并画出它的所有对称轴.5.(2021秋•灌阳县期末)画出下列轴对称图形的所有对称轴。
6.(2021秋•峄城区期末)画出下面每组图形中的所有的对称轴。
7.用镜子照一照.看看是什么?8.(2019秋•兴宾区期中)画一条虚线,把对称的图片分成完全一样的两部分.9.(2018春•端州区月考)下面的图案各是从哪张纸上剪下来的?请连线.10.(2022秋•离石区期末)请按照给出的对称轴画出如图图形的轴对称图形。
11.(2022秋•渭滨区期末)以虚线为对称轴,画出下列图形的轴对称图形。
12.(2022春•锡山区期中)画一画画出下列图形的对称轴。
(画出一条即可)13.(2021秋•广平县期末)画出如图图形的一条对称轴。
14.如图图2是图1在镜子中的图象,但有两处画错了,你能找出并圈起来吗?快试试看吧!15.(2014春•海原县月考)如图的图案各是从哪张纸上剪下来的?请连线.16.如图各图案中,属于轴对称图形的在括号里打“√”.17.下面的交通标志哪些是轴对称图形?画“〇”18.如图哪些图形是轴对称图形?画“〇”.19.找规律,画一画.20.王阿姨是远近闻名的巧裁缝。
一次,她拿着两块边角料(如图),横比竖量,只剪了两刀,就神奇地拼出了一个正方形。
你知道王阿姨是怎样剪的吗?在图中画一画。
21.(2022秋•怀柔区期末)以虚线为对称轴,画出下面图形的轴对称图形。
22.(2022秋•渑池县期末)请你用圆规和三角尺,在下面的方格纸上设计一个圆和正方形组成的轴对称图形。
《画对称图形》教学设计3篇
《画对称图形》教学设计第一篇:教学目标与教学内容介绍一、教学目标1.了解对称图形的基本概念及相关术语。
2.掌握对称轴的画法和对称图形的绘制方法。
3.能够通过对称操作,发现对称图形的性质,并进行简单的证明。
4.培养学生的逻辑思维能力、想象力和良好的观察力和绘画技能。
二、教学内容本次教学将围绕对称图形的概念、对称轴的画法和对称图形的绘制方法展开。
同时,通过一定的练习和讲解,让学生了解对称操作的基本性质,并进行简单的证明。
教学具体内容如下:1.对称图形的概念和相关术语。
2.对称轴的类型和画法。
3.对称图形的绘制方法。
4.对称操作的基本性质及证明。
5.对称图形的应用。
三、教学方法1.讲授法:通过讲解基本概念和相关知识点,让学生对对称图形有全面的认识和了解。
2.示范法:通过教师的示范,让学生了解对称轴的画法和对称图形的绘制方法。
3.练习法:通过练习,让学生掌握对称操作的基本性质和对称图形的绘制方法。
4.互动交流法:通过课堂提问和小组讨论等方式,让学生积极参与课堂,提高学习效果。
四、教学重点和难点1.教学重点:对称图形的基本概念和相关术语、对称轴的画法和对称图形的绘制方法。
2.教学难点:对称操作的基本性质及证明。
五、教学准备1.教具准备:黑板、彩笔、纸张、尺子、圆规、颜色笔等。
2.教材准备:教材《初中数学(下册)》(新人教版)第九章第一节。
3.教学 PPT:利用 PPT 等多媒体设备辅助讲解。
以上是本次教学的目标、内容、方法和准备,下面将具体展开教学设计和实施。
第二篇:教学流程与课堂设计一、教学流程1.引入(5 分钟)通过一个简单的对称图形,引出对称图形的概念和相关术语,引导学生了解对称轴的画法和对称图形的绘制方法。
2.讲解(15 分钟)讲解对称图形的概念和相关术语,介绍对称轴的类型和画法,规范对称图形的绘制方法。
3.示范(10 分钟)通过教师的示范,让学生了解对称轴的画法和对称图形的绘制方法,考察学生的绘图技能。
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一、回忆轴对称的相关知识
1. 轴对称图形与轴对称。 2. 对称轴。 3. 对称点。
对称点
A1
C1
B1
图 9.1.3
二、回忆昨天所学的知识
(1)线段和角都是轴对称图形吗?各有 几条对称轴? (2)什么叫线段的垂直平分线?它有 什么性质?
三、检查自己对知识的掌握程度
无数 1、到线段两个端点距离相等的点有____个, 无数 平分一条已知线段的直线有____条;垂直 1 平分一条已知线段的直线有____条. 无数 2、到角两边距离相等的点有____个;
3、半圆是轴对称图形吗?如果是,它有 几条对称轴?
如果没有方格子,而又不能折叠,你还 能比较准确的画出图形的对称轴吗?
(1)
画完图后请思考下面的问题:
①能总结你画对称轴的方法吗? ②你ቤተ መጻሕፍቲ ባይዱ如何判断对称轴的位置的呢? ③连接对称点的线段与对称轴有什么关系?
(1)
(2)
结论:
连接对称点的线段被对称轴垂直平分.
(第1题)
(第 3 题)
分小组动手活动(P88练习2)
(3)
各位小组成员可要积极参与、分工合作,看哪组 完成得又快又好。祝大家合作愉快!!!
三、小结:
1. 画图形的对称轴的方法: (1)找出轴对称图形的任意一组对称点。 (2)连结对称点。 (3)画出对称点所连线段的垂直平分线, 就是该图形的对称轴
P87做一做 如图,点A和点A’关于某条直线成轴对称, 你能画出这条直线吗?
A
.
.
A’
思考: 通过前面的画图练习,你能总结出画 图形的对称轴的方法?
请总结出你画图形的对称轴的画法:
(1)找出轴对称图形的任意一组对称点。 (2)连结对称点。 (3)画出对称点所连线段的垂直平分线, 就可以得到该图形的对称轴。
2.轴对称性质: 如果一个图形关于某一条直线对称,那 么连结对称点的线段的垂直平分线就是 该图形的对称轴.
A C D B
A C E
B
C A
B B
A
A’
B’
E
D
C C’
画图的同时请思考: 轴对称有什么性质?
小组合作讨论、探索—— 轴对称或轴对称图形有些什么性质?
① 连结对称点的线段的垂直平分线就 是该图形的对称轴. ② 如果它们的对应线段或延长线相交, 那么交点一定在对称轴上。 ③两个图形是全等形。
课后练习:请完成P88练习第1、2 、3题。