“解一元一次不等式”教案

“解一元一次不等式”教案 指导教科目 数学 班级 七年级十班 师 剩余课总课时 1 计划 项目进度计划表范例计划下载计划下载计划下载课程教学计划下载 课时 1 0 时 课题 解一元一次不等式 授课时间 备课时间 1、体会解不等式的步骤，体会数学学习中比较和转化知识与的作用。 2、用数轴表示解集，启发学生对数形结合思想的进一技能 步理解和掌握。 1、介绍一元一次不等式的概念。 过程与2、引导学生体会通过综合利用不等式的概念和基本性 质解不等式的 方法 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 。 教学目标 发展 3、练习巩固，能将本节内容与上节内容联系起来。 1、在教学过程中引导学生体会数学中的比较和转换 思想。 情感与2、通过类比一元一次方程的解法，从而更好地掌握一 元一次不等式的解法。 态度 3、通过学生的讨论，让学生进一步体会集体的作用， 培养集体合作的精神。 1、掌握一元一次不等式的解法。 2、掌握解一元一次不等式的步骤，并能准确求出解重点 教学重点 集。 能将文字语言转化为数学语言，从而完成对问题的与难点 难点 解决。 教材 民兵爆破地雷教材pdf初中剪纸校本课程教材衍纸校本课程教材排球校本教材中国舞蹈家协会第四版四级教材 中没有给出解法的一般步骤，所以在教学中要注意让学生 经历将所给的不等式转化为简单不等式的过程，并通过学生的讨 论、交流使学生经历知识的形成和巩固的过程。在教学的过程中，教学突破 将本节知识与上节课联系起来，重视将解集表示在数轴上，从而知 指导学生体会用数形结合的方法解决问题。 教学内容 filing. 3, the safety records should be complete in time, and continues to project completion. 4, project safety production management information system of the Ministry of health planning, implementation, c d improved checking and correction, a total of four volumes. Construction and environmental protection in other security measures, such as the first civilization construction and environmental management objectives and civilized construction objectives of civil strive to obtain "safe and civilized model site of Zhuhai city" title. Environmental management goal 1, noise, dust, wastewater discharge standards; reducing and controlling the generation of solid waste; 2, reduce the impact of noise on the surrounding environment, noise complaints decreased by 20%; 3, reduce the consumption of raw materials and energy, construction raw material usage below the standards set by the State, average savings rate of 1% the following three materials. Section II project the civilization construct management system to establish a sound and civilized construction system, at all levels and all departments effective implementation of responsibility system for civil construction, ensure the goal of civilization. Ordinal system name 1 education system extensively and civilized construction management education, improve the overall construction initiative, ideology, so that workers form a building 一、复习引入: 师:同学们好，在前面的几节课中，我们分别学习了认识不等式，不等式的解集以及不等式的简单变形。细心地同学会发现，我们在前面的学习过程中所遇到的不等式都有一个共同的特点:哪这个共同的特点是什么呢,有同学发现了吗,(小组讨论1分钟，然后请学生回答) 生:都只含有一个未知数，且含未知数的式子是整式，未知数的次数是1。 二、讲授新课: 1、一元一次不等式的概念: 师:非常好，在前面学习方程时，我们把只含有一个未知数，且未知数的次数是1的整式方程叫做一元一次方程。与一元一次方程类似，我们也将:只含有一个未知数，且含未知数的式子是整式，未知数的次数是1的不等式叫做一元一次不等式。 师:同样，我们在判断一个不等式是否为一元一次不等式时，就必须满足这 三个条件:?只含有一个未知数，?且含未知数的式子是整式，?未知数的次数是1。(用红色粉笔标注)，强调:这三个条件缺一不可。 师:好，下面就请同学们，拿出导学案完成导学案中第八页上的当堂训练中 的第2题。 判断下列各式中是一元一次不等式的是, (学生先独立判断，然后请学生说出结果并阐述理由) 2、解一元一次不等式(主要讲授总结出:解一元一次不等式的步骤) 师:好，在上一节课，我们学习了利用不等式的性质来解了一些比较简单的 一元一次不等式，那么解一元一次不等式的步骤有哪些呢,是否也和我们解一元一次方程的步骤类似呢, 师:下面我们一起来解一些一元一次不等式: 例3:解下例不等式，并将解集在数轴上表示出来。 2x,1,4x，13 ? ? 2(5x，3),x,3(1,2x) 2x,1,4x，13解:? (首先，利用不等式的性质对不等式进行移项;) 2x,4x,13，1 移项: (移项之后合并同类项) ,2x,14合并同类项: (最后利用不等式的性质3，化系数为1;注意化 x,,7化系数为1: 系数为1时，不等式两边同乘的是一个负数，不 等号的方向要改变) 数轴表示为:(在次强调:用数轴表示解集时，?首先用直尺画出数轴，确 定出三要素:方向、原点、单位长度;?定边界:有等号用实心点表示，无等号用空心的圆圈表示;?定方向:大于向右，小于向左。) filing. 3, the safety records should be complete in time, and continues to project completion. 4, project safety production management information system of the Ministry of health planning, implementation, c d improved checking and correction, a total of four volumes. Construction and environmental protection in other security measures, such as the first civilization construction and environmental management objectives and civilized construction objectives of civil strive to obtain "safe and civilized model site of Zhuhai city" title. Environmental management goal 1, noise, dust, wastewater discharge standards; reducing and controlling the generation of solid waste; 2, reduce the impact of noise on the surrounding environment, noise complaints decreased by 20%; 3, reduce the consumption of raw materials and energy, construction raw material usage below the standards set by the State, average savings rate of 1% the following three materials. Section II project the civilization construct management system to establish a sound and civilized construction system, at all levels and all departments effective implementation of responsibility system for civil construction, ensure the goal of civilization. Ordinal system name 1 education system extensively and civilized construction management education, improve the overall construction initiative, ideology, so that workers form a building 解:? 【 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 】这个不等式含有括号，首先我要 2(5x，3),x,3(1,2x) 10x，6,x,3，6x 去括号: 先去掉括号，去括号时，一定要注意符号。 10x,7x,,3,6移项: (即括号外的这个数为负时，去掉括号后， 3x,,9合并同类项: 括号里的数要改变符号。) x,,3化系数为1: 然后，利用不等式的性质1和2，分别移项 和化系数为1。 师:好，然后画出数轴，表示这个不等式的解集:(边画边强调表示不等式解 集的步骤) 3x,1x，4例4:当取何值时，代数式与的值的差大于1。 x32 x，43x,1,,1【分析】抓关键词:它们值的差大于1，即 32 x，43x,1,,1解:由题意得: 师:这个不等式含有分母，我们要解它 32 去分母: 首先要将分母去掉，所以两边同乘以6(分 2(x，4),3(3x,1),6 2x，8,9x，3,6去括号: 母3和2的最小公倍数);请同学们想一想， 2x,9x,6,8,3移项: 我们在不等式的两边同乘以6时，不等号的 ,7x,,5合并同类项: 方向会不会改变呢, 5x,化系数为1: 生:不会，因为6是一个正数。 7 5当取小于的任何数时， 师:对～注意:在去分母时，不等式 x？7 3x,1x，4代数式与的值的差大于1。 的每一项都要乘以6，千万不要漏乘。 32 师:好～现在请同学们观察一下，我们解得这三个一元一次不等式。总结一 下解一元一次不等式的步骤有哪些，应该特别注意什么,(学生先独立思考1分钟，在进行小组讨论2分钟) 生:步骤有:去分母;去括号;移项;合并同类项;系数化为1; 生:应特别注意化系数为1时，当乘以(或除以)一个负数时，不等号的方向要发生改变。 生:还应注意的有:去分母时，不等式的两边都要同时乘以最小公倍数，不能漏乘; 去括号是，如果括号外的数为负数，去掉括号后，括号里的数要改变符号; 三、总结知识 师:好下面来总结一下，我们今天这节课主要学习了两个方面的内容: filing. 3, the safety records should be complete in time, and continues to project completion. 4, project safety production management information system of the Ministry of health planning, implementation, c d improved checking and correction, a total of four volumes. Construction and environmental protection in other security measures, such as the first civilization construction and environmental management objectives and civilized construction objectives of civil strive to obtain "safe and civilized model site of Zhuhai city" title. Environmental management goal 1, noise, dust, wastewater discharge standards; reducing and controlling the generation of solid waste; 2, reduce the impact of noise on the surrounding environment, noise complaints decreased by 20%; 3, reduce the consumption of raw materials and energy, construction raw material usage below the standards set by the State, average savings rate of 1% the following three materials. Section II project the civilization construct management system to establish a sound and civilized construction system, at all levels and all departments effective implementation of responsibility system for civil construction, ensure the goal of civilization. Ordinal system name 1 education system extensively and civilized construction management education, improve the overall construction initiative, ideology, so that workers form a building ? 一元一次不等式的概念。(这部分，要求同学们要能判断一个不等式是否为 一元一次不等式，注意三个条件); ? 解一元一次不等式的步骤(特别注意:系数化为1时，同乘以(或除以)一 个负数时，不等号要变号)。 四、巩固练习 师:请同学们拿出导学案，翻到第八页，做当堂训练中的第5题。(请两个学生上黑板做，其余学生在下面独立完成;最后教师点评、总结) 五、布置作业 1、教材练习48页的第1题，第2题，第3题 2、教材精习44页第3课时 六、板书 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 8.2.3解一元一次不等式 例4:当取何值时，代数式 1、 一元一次不等式的概念 例3:解下列不等式，并将解集表与的值的差大于1。 ?只含有一个未知数，?所含未知数示出来 解:由题意得:的式子是整式，?未知数的次数为1 2x,1,4x，13x，43x,1? ,,1(三个条件，缺一不可) 32? 2(5x，3),x,3(1,2x)2、 解一元一次不等式的步骤: 去分母: ?去分母 ?去括号 去括号: 2x,1,4x，13解:? ? ?移项 ?合并同类项 移项: 2x,4x,13，1移项: ?化系数为1 合并同类项: ,2x,14合并同类项: 系数化为1: x,,7系数化为1: 数轴表示为: 5所以当取小于的数x7 时，这两个代数式的值的差 大于1。 教学反思 1、本节介绍了用一元一次不等式解决实际问题，所以在此过程中应通过学生从多个方面探索解法，从而能灵活的利用不等式解决实际问题。 2、通过组织学生分析、讨论，各抒己见，激发学生的学习兴趣，同时强化学生思维的灵敏性和多面性。 filing. 3, the safety records should be complete in time, and continues to project completion. 4, project safety production management information system of the Ministry of health planning, implementation, c d improved checking and correction, a total of four volumes. Construction and environmental protection in other security measures, such as the first civilization construction and environmental management objectives and civilized construction objectives of civil strive to obtain "safe and civilized model site of Zhuhai city" title. Environmental management goal 1, noise, dust, wastewater discharge standards; reducing and controlling the generation of solid waste; 2, reduce the impact of noise on the surrounding environment, noise complaints decreased by 20%; 3, reduce the consumption of raw materials and energy, construction raw material usage below the standards set by the State, average savings rate of 1% the following three materials. Section II project the civilization construct management system to establish a sound and civilized construction system, at all levels and all departments effective implementation of responsibility system for civil construction, ensure the goal of civilization. Ordinal system name 1 education system extensively and civilized construction management education, improve the overall construction initiative, ideology, so that workers form a building filing. 3, the safety records should be complete in time, and continues to project completion. 4, project safety production management information system of the Ministry of health planning, implementation, c d improved checking and correction, a total of four volumes. Construction and environmental protection in other security measures, such as the first civilization construction and environmental management objectives and civilized construction objectives of civil strive to obtain "safe and civilized model site of Zhuhai city" title. Environmental management goal 1, noise, dust, wastewater discharge standards; reducing and controlling the generation of solid waste; 2, reduce the impact of noise on the surrounding environment, noise complaints decreased by 20%; 3, reduce the consumption of raw materials and energy, construction raw material usage below the standards set by the State, average savings rate of 1% the following three materials. Section II project the civilization construct management system to establish a sound and civilized construction system, at all levels and all departments effective implementation of responsibility system for civil construction, ensure the goal of civilization. Ordinal system name 1 education system extensively and civilized construction management education, improve the overall construction initiative, ideology, so that workers form a building