解析:从各点的位置可以发现A1(1,0),A2(1,1),A3(-1,1),A4(-1,-1),A5(2,-1),A6(2,2),A7(-2,2),A8(-2,-2),A9(3,-2),A10(3,3),A11(-3,3),A12(-3,-3),….仔细观察每四个点的横、纵坐标,发现存在着一定规律性.因为2015=503×4+3,所以点A2015在第二象限,纵坐标和横坐标互为相反数,所以A2015的坐标为(-504,504).故填(-504,504).方法总结:解决此类题常用的方法是通过对几种特殊情况的研究,归纳总结出一般规律,再根据一般规律探究特殊情况.三、板书设计轴对称与坐标变化关于坐标轴对称作图——轴对称变换通过本课时的学习,学生经历图形坐标变化与图形的轴对称之间的关系的探索过程,掌握空间与图形的基础知识和基本作图技能,丰富对现实空间及图形的认识,建立初步的空间观念,发展形象思维,激发数学学习的好奇心与求知欲.教学过程中学生能积极参与数学学习活动,积极交流合作,体验数学活动的乐趣.
(一)复习导入 师:什么是体积?生:物体所占空间的大小是物体的体积。师:怎样求长方体和正方体的体积?生:长方体的体积=底面积×高 正方体的体积=底面积×高师:圆的面积计算公式是怎样推导出来的?课件出示:生:把圆转化成长方形,长方形的长等于圆柱底面周长的一半,宽等于半径,所以圆的面积:S = πr2猜测:把圆柱转化成什么立体图形来推导圆柱的体积公式呢?呢?今天我们一起来探讨这个问题。板书课题:圆柱的体积。
五. 班会目标: 1. 让同学们深入了解“三爱三节”的具体含义。 2. 教导学生如何践行“三爱三节”。 3. 通过主题班会的学习,培养学生良好的行为习惯,使“三爱三节”真正的融入到以后的学习生活中。 4. 利用主题班会普及“三节”小知识。 六. 班会准备: 1. 班干部负责班会黑板装饰,主要体现“三爱三节”的主题。 2. 提前通知学生通过询问、上网、看书等,收集节水,节粮,节电小妙招。 3. 将班级划分成小组,选出发言人,便于班会进行过程中汇总小组意见发言。
(一)、亚太经济合作组织的宗旨和作用1、亚太经合组织简介:(1)、地位——当今世界最大的区域性经济合作组织(2)、性质——是促进亚太国家和地区经济合作、推动共同发展的主要机构。亚太经济合作组织(APEC,简称亚太经合组织),是当今世界最大的区域性经济合作组织,是促进亚太国家和地区经济合作、推动共同发展的主要机构。相关链接:1989年11月,在澳大利亚的倡议下,澳大利亚、美国、加拿大、日本、韩国、新西兰和东盟六国的外交与经济部长在澳大利亚首都堪培拉召开部长级会议,正式宣告亚太经合组织成立。此后,该组织不断扩大,到2004年底共有21个成员,既有美国、日本等发达国家,也有中国、马来西亚、墨西哥等发展中国家。亚太经合组织的宗旨是:为本地区人民的共同利益而保持经济的增长与发展,促进成员间经济的相互依存,加强开放的多边贸易体制,减少区域贸易和投资壁垒。
三、学情与教材分析《积的变化规律》是九年义务教育课程标准实验教科书小学数学四年级上册第三单元的内容。本课例以一组乘法算式为载体,引导学生探索当一个因数不变时,另一个因数与积的变化规律。在学生已经掌握了乘法运算的基本技能的基础上,在乘法运算中探索积的变化规律。通过这个过程的探索,学生将会经历研究问题——归纳发现规律——解释说明规律——举例验证规律四个层次的学习过程。学生将会用到观察、计算、自主探索、合作交流等学习手段,并最终发现规律,归纳与验证规律,从而有效的培养学生探索与推理的能力,让学生体会事物间是密切相关的,受到辩证思想的启蒙教育。例题的设计分三个层次:1、教材设计了一组乘法算式,引导学生在观察,计算,对比的基础上自主发现因数变化引起积的变化规律。
第三个规律,商不变的规律。这是本课的重点内容。有了两次的探究经验,这一规律的学习与理解,可以完全放手让学生自主进行。猜想如果商不变,被除数、除数会发生什么变化呢?学生根据已有的经验,可能会有不同猜想,我要求学生带着问题通过计算、观察、比较、主动探讨总结出:被除数和除数同时扩大(或缩小)相同的倍数(0除外)商不变。利用合作学习,通过动脑动口动手,既提高学生解决问题的学习能力,又培养了合作学习的意识和习惯。给学生提供展示研究成果的机会,体验成功。需要教师提醒的是“有没有被除数和除数同时乘或除以不相同的数,商也不变的?”学生举反例加以说明并指出“相同的倍数不包括0”。设计这个环节,也有意让学生去验证商不变性质。学生在表述时,对于逻辑的严密性和语言的完整性需要老师及时指导,在突出重点的同时培养学生的语言表达能力。整个环节在验证的基础上,步步深化商的变化规律,为学生应用新知做好铺垫。
1、结合具体生活场景,能运用所学的乘法口诀解决简单的实际问题,通过图与式的对应,进一步理解乘法的意义。 2、能熟练运用口诀进行计算,提高灵活运用口诀解决实际问题的能力。 3、体会数学与实际生活的联系,培养用数学的意识,体验口诀在解决问题中的作用。 运用所学乘法解决简单的实际问题。 结合实际情景理解乘法的意义。 1、口算: 5×2=10 6×2=12 8×5=40 2×7=14 5×9=45 3×5=15 2×6=12 2×9=18 4×2=8 2、谈话导入:在前面的学习中,我们认识了乘法,而且还学习了2和5的乘法口诀。这节课,老师想请同学们用这些跟乘法有关的知识来帮助老师一起解决生活中遇到的问题,一起来看一看吧。快乐休息时间到了,学校的大操场突然热闹起来了,你们一定非常喜欢课件活动吧!看,操场上同学们有的在玩老鹰捉小鸡的游戏,有的在进行乒乓球比赛,有的在跳绳,还有的在踢毽子……真热闹啊!
8.一束光线从点A(3,3)出发,经过y轴上点C反射后经过点B(1,0)则光线从A点到B点经过的路线长是( )A.4 B.5 C.6 D.7第四环节课堂小结1、关于y轴对称的两个图形上点的坐标特征:(x , y)——(- x , y)2、关于x轴对称的两个图形上点的坐标特征:(x , y)——(x , - y)3、关于原点对称的两个图形上点的坐标特征:(x , y)——(- x , -y)第五环节布置作业习题3.5 1,2,3四、 教学反思通过“坐标与轴对称”,经历图形坐标变化与图形的轴对称之间的关系的探索过程, 掌握空间与图形的基础知识和基本技能,丰富对现实空间及图形的认识,建立初步的空间观念,发展形象思维,激发学生对数学学习的好奇心与求知欲,学生能积极参与数学学习活动;积极交流合作,体验数学活动充满着探索与创造。教学中务必给学生创造自主学习与合作交流的机会,留给学生充足的动手机会和思考空间,教师不要急于下结论。事先一定要准备好坐标纸等,提高课堂效率。
二项式定理形式上的特点(1)二项展开式有n+1项,而不是n项.(2)二项式系数都是C_n^k(k=0,1,2,…,n),它与二项展开式中某一项的系数不一定相等.(3)二项展开式中的二项式系数的和等于2n,即C_n^0+C_n^1+C_n^2+…+C_n^n=2n.(4)在排列方式上,按照字母a的降幂排列,从第一项起,次数由n次逐项减少1次直到0次,同时字母b按升幂排列,次数由0次逐项增加1次直到n次.1.判断(正确的打“√”,错误的打“×”)(1)(a+b)n展开式中共有n项. ( )(2)在公式中,交换a,b的顺序对各项没有影响. ( )(3)Cknan-kbk是(a+b)n展开式中的第k项. ( )(4)(a-b)n与(a+b)n的二项式展开式的二项式系数相同. ( )[解析] (1)× 因为(a+b)n展开式中共有n+1项.(2)× 因为二项式的第k+1项Cknan-kbk和(b+a)n的展开式的第k+1项Cknbn-kak是不同的,其中的a,b是不能随便交换的.(3)× 因为Cknan-kbk是(a+b)n展开式中的第k+1项.(4)√ 因为(a-b)n与(a+b)n的二项式展开式的二项式系数都是Crn.[答案] (1)× (2)× (3)× (4)√
(一)复习导入 1. 师:同学们,你们去过这些景区吗?(课件第2张)鸟巢、水立方、市容卫生、绿化建设、城市规划建设、航天事业的发展。 2.师:我国的经济建设日新月异,人民生活的不断提高,基础建设全面展开。你知道这些设施的费用是从哪儿来的吗?生:这些设施的费用都是政府投资的,是国家出钱建设的。师:国家的钱又是从哪儿来的?生:国家的财源主要来自税收。3.导出纳税、税率。(课件第3张)生1:纳税是根据国家税法的有关规定,按照一定的比率把集体或个人收入的一部分缴纳给国家。生2:税收是国家收入的主要来源之一。国家用收来的税款发展经济、科技、教育、文化和国防等事业。生3:每个公民都有依法纳税的义务哦!这节课我们就来学习有关税收的知识。板书课题:税率【设计意图】 联系学生的生活实际,使学生知道每个公民都有依法纳税的义务,增强学生的纳税意识。(二)探究新知 1、探究税率的含义。(课件第4张)(1)你知道哪些纳税项目?应该怎样缴纳税款呢?生1:税收主要分为消费税、增值税、营业税和个人所得税等几类。生2:缴纳的税款叫做应纳税额,应纳税额与各种收入(销售额、营业额……)的比率叫做税率。2、探索应纳税额的计算。(课件第5张)(1)有一家饭店10月份的营业额是30万元,如果按营业额的5%缴纳营业税,这家饭店10月份应缴纳营业税多少万元?(2)小组讨论:你是怎样想的?说说你的思考过程。(3)汇报交流:(课件第6张)生1:缴纳的营业税是营业额的5%。生2:求营业额的5%是多少,用乘法计算。生3:30×5%=1.5(万元)答:这家饭店10月份应缴纳营业税1.5万元。3、做一做。(课件第7张)(1)李阿姨的月工资是5000元,扣除3500元个税免征额后的部分需要按3%的税率缴纳个人所得税。她应缴个人所得税多少元?小组合作:你会做吗?说说你的想法。汇报交流:(课件第8张)生1:“扣除3500元个税免征额后的部分”这句话是什么意思?生2:要从工资总数里减去3500元,剩下的钱按3%的税率缴税。生3:(5000-3500)×3%=1500×0.03=45(元)答:她应缴个人所得税45元。 (2)计算某商场5月份商品零售营业税。(课件第9张) 你会做吗?说说你的想法。小组合作:你是怎样想的?说说你的思考过程。(课件第10张)汇报交流:(课件第11张)生:先求总营业额,再求营业税。 72+35+46+21+56=230(万元)230×5%=1.15(万元) 答:这个商场5月份商品零售营业税是1.15万元。 (3)丰华商场9月份按规定缴了1.85万元的营业税,他们纳税的税率是5%。这个商场9月份的营业额是多少万元?(课件第12张)生1:把营业额看做单位“1”,求营业额,做除法。生2:1.85÷5%=1.85÷0.05=370(万元)答:这个商场9月份的营业额是370万元。生3:把营业额看做单位“1”,求营业额,也可以列方程解答。(课件第13张)解:设这个商场9月份的营业额是x万元。
3.下结论.依据均值和方差做出结论.跟踪训练2. A、B两个投资项目的利润率分别为随机变量X1和X2,根据市场分析, X1和X2的分布列分别为X1 2% 8% 12% X2 5% 10%P 0.2 0.5 0.3 P 0.8 0.2求:(1)在A、B两个项目上各投资100万元, Y1和Y2分别表示投资项目A和B所获得的利润,求方差D(Y1)和D(Y2);(2)根据得到的结论,对于投资者有什么建议? 解:(1)题目可知,投资项目A和B所获得的利润Y1和Y2的分布列为:Y1 2 8 12 Y2 5 10P 0.2 0.5 0.3 P 0.8 0.2所以 ;; 解:(2) 由(1)可知 ,说明投资A项目比投资B项目期望收益要高;同时 ,说明投资A项目比投资B项目的实际收益相对于期望收益的平均波动要更大.因此,对于追求稳定的投资者,投资B项目更合适;而对于更看重利润并且愿意为了高利润承担风险的投资者,投资A项目更合适.
对于离散型随机变量,可以由它的概率分布列确定与该随机变量相关事件的概率。但在实际问题中,有时我们更感兴趣的是随机变量的某些数字特征。例如,要了解某班同学在一次数学测验中的总体水平,很重要的是看平均分;要了解某班同学数学成绩是否“两极分化”则需要考察这个班数学成绩的方差。我们还常常希望直接通过数字来反映随机变量的某个方面的特征,最常用的有期望与方差.二、 探究新知探究1.甲乙两名射箭运动员射中目标靶的环数的分布列如下表所示:如何比较他们射箭水平的高低呢?环数X 7 8 9 10甲射中的概率 0.1 0.2 0.3 0.4乙射中的概率 0.15 0.25 0.4 0.2类似两组数据的比较,首先比较击中的平均环数,如果平均环数相等,再看稳定性.假设甲射箭n次,射中7环、8环、9环和10环的频率分别为:甲n次射箭射中的平均环数当n足够大时,频率稳定于概率,所以x稳定于7×0.1+8×0.2+9×0.3+10×0.4=9.即甲射中平均环数的稳定值(理论平均值)为9,这个平均值的大小可以反映甲运动员的射箭水平.同理,乙射中环数的平均值为7×0.15+8×0.25+9×0.4+10×0.2=8.65.
4.写出下列随机变量可能取的值,并说明随机变量所取的值表示的随机试验的结果.(1)一个袋中装有8个红球,3个白球,从中任取5个球,其中所含白球的个数为X.(2)一个袋中有5个同样大小的黑球,编号为1,2,3,4,5,从中任取3个球,取出的球的最大号码记为X.(3). 在本例(1)条件下,规定取出一个红球赢2元,而每取出一个白球输1元,以ξ表示赢得的钱数,结果如何?[解] (1)X可取0,1,2,3.X=0表示取5个球全是红球;X=1表示取1个白球,4个红球;X=2表示取2个白球,3个红球;X=3表示取3个白球,2个红球.(2)X可取3,4,5.X=3表示取出的球编号为1,2,3;X=4表示取出的球编号为1,2,4;1,3,4或2,3,4.X=5表示取出的球编号为1,2,5;1,3,5;1,4,5;2,3,5;2,4,5或3,4,5.(3) ξ=10表示取5个球全是红球;ξ=7表示取1个白球,4个红球;ξ=4表示取2个白球,3个红球;ξ=1表示取3个白球,2个红球.
【词汇精讲】highlight n.最好或最精彩的部分 vt.突出;强调;使醒目One of the highlights of the trip was seeing the Taj Mahal.这次旅行的亮点之一是参观泰姬陵。Your resume should highlight your skills and achievements.你的简历应该突出你的技能和成就。The report highlights the major problems facing society today.报告强调了当今社会所面临的主要问题。I’ve highlighted the important passages in yellow.我用黄色标出了重要段落。7.Edmonton is freezing cold in winter,with daily temperatures averaging -10 ℃.埃德蒙顿冬季寒冷,日平均气温为-10°C。【词汇精讲】freezing adj.极冷的;冰冻的Leave a basin of water outside in freezing weather.在冰冻的天气里,放一盆水在室外。It’s freezing cold outside so wear a warm coat.外面超冷的,所以穿一个暖和一点的外套吧。8.It was not until 9:30 a.m.that they finally reached the capital of Ontario,Toronto.直到上午9时30分,他们才终于到达多伦多的首府安大略省。【句式剖析】本句是一个强调句,强调的是句子的时间状语until 9:30。含有not...until...的句子的强调句为It is not until...that...,that后面的句子要用肯定形式。It was not until then that I suddenly realized nobody was happier than I was.直到那时我才突然意识到没有人比我更幸福了。
1. We'll need ten months at least to have the restaurant decorated.2.Some traditional Chinese dishes from before the Ming Dynasty are still popular today.3.My grandpa's breakfast mainly includes whole grain biscuits and a glass of milk.4.People in this area would eat nearly a kilo of cheese per week.5. We enjoyed a special dinner in a fancy restaurant where the waiters all wore attractive suits.6. He prefers this brand of coffee which, as he said, has an unusually good flavor.Key:1. at a minimum 2. prior to3. consist of4. consume5. elegant6. exceptionalStep 5:Familiarize yourself with some food idioms by matching the meaning on the right with the colored words on the left.1.Public concern for the health of farm animals has mushroomed in the UK2.Anderson may be young but he's certainly rolling to doing dough!3.George is a popular lecturer. He often peppers his speech with jokes.4.As the person to bring home the bacon, he needs to find a stable job.5 He is often regarded as a ham actor for his over emphasized facial expressions. The media reported that these companies had treated pollution as a hot potato. 6.The media reported that these companies had treated pollution as a hot potato.7.Don't worry about the test tomorrow. It's going to be a piece of cake!8. It's best to fold the swimming ring when it is as flat as a pancake.A. completely flatB. something that is very easy to do C.an issue that is hard to deal withD.to include large numbers of somethingE.to earn on e's living to support a familyF. wealthyG.to rapidly increase in numberH. an actor who performs badly, especially by over emphasizing emotions
The activity theme of this section is to design various activities around the key words in the first text. Therefore, the activities require students to pay attention to the spelling of words. On the other hand, let students grasp the meaning of words more accurately through sentences and short texts. This kind of teaching design also helps to improve the ability of using English thinking.1. Cultivating students' ability to use word formation to induce and memorize vocabulary, and the ability to use lexical chunks to express meaning.2. Guide the students to think independently and use the correct form of words to complete sentences3. Cultivate students' habit of using lexical chunks to express language completely, guide students to draw words in sentences quickly, pay attention to word collocation, so as to accumulate more authentic expressions4. Instruct students to create sentences with the chunks.1. Enable students to use the language points in the real situation or specific contexts flexibly and appropriately.2. Guiding the Ss to use unit topic words and the sentence patterns in a richer context.Step1: Think of a word that best fits each definition.1. to remember sth2.to accept, admit, or recognize sth or the truth/existence of sth3. the process of changing sth or yourself to suit a new situation4 .to make sb feel less worried or unhappy5. a strong desire to achieve sth
你校英语报计划出版一期急救常识专刊,现面向全校学生公开征集稿件,你有意参加。请你根据下面提示内容,用英语写一篇短文,介绍在车祸现场对伤者进行急救的方法和步骤。1.确保现场的安全;2.询问伤者,确保其呼吸正常;3.检查伤口,如流血则应采取止血措施;4.如需急救,确保其处于康复位置。注意:1.词数80左右;2.可以适当增加细节,以使行文连贯。参考词汇:康复位置 recovery positionAs we all know, having a knowledge of first aid can make a great difference in our daily life. If a traffic accident happens and someone is injured, the following steps can be used to treat the injured.In the first place, we should make sure that the accident scene is safe so that we won’t get hurt. We should ask the injured person if he is OK, and see if he is breathing. What’s more, we should check for cuts and wounds. If he is bleeding badly, it is vital that we should try to stop the bleeding by applying pressure to the injury. This is because if a person loses too much blood, he may die. If necessary, take the injured person to the hospital as soon as possible.Do remember: when giving first aid, please be sure to place the person in a recovery position.
Her tutor told her to acknowledge __________ other people had said if she cited their ideas, and advised her _______(read) lots of information in order to form __________wise opinion of her own.Now halfway __________ her exchange year, Xie Lei felt much more at home in the UK. She said __________ (engage) in British culture had helped and that she had been__________ (involve) in social activities. She also said while learning about business, she was acting as a cultural messenger __________(build) a bridge between the two countries. keys:Xie Lei, a 19yearold Chinese student, said goodbye to her family and friends in China and boarded (board) a plane for London six months ago in order to get a business qualification. She was ambitious(ambition) to set up a business after graduation. It was the first time that she had left (leave) home.At first, Xie Lei had to adapt to life in a different country. She chose to live with a host family, who can help with her adaptation (adapt) to the new culture. When she missed home, she felt comforted (comfort) to have a second family. Also Xie Lei had to satisfy academic requirements. Her tutor told her to acknowledge what other people had said if she cited their ideas, and advised her to read lots of information in order to form a wise opinion of her own.Now halfway through her exchange year, Xie Lei felt much more at home in the UK. She said engaging (engage) in British culture had helped and that she had been involved (involve) in social activities. She also said while learning about business, she was acting as a cultural messenger building a bridge between the two countries.
The theme of this part is to write an article about healthy diet. Through reading and writing activities, students can accumulate knowledge about healthy diet, deepen their understanding of the theme of healthy diet, and reflect on their own eating habits. This text describes the basic principles of healthy diet. The author uses data analysis, definition, comparison, examples and other methods. It also provides a demonstration of the use of conjunctions, which provides important information reference for students to complete the next collaborative task, writing skills, vivid language materials and expressions.1. Teach Ss to learn and skillfully use the new words learned from the text.2. Develop students’ ability to understand, extract and summarize information.3. Guide students to understand the theme of healthy diet and reflect on their own eating habits.4. To guide students to analyze and understand the reading discourse from the aspects of theme content, writing structure, language expression, etc., 5. Enable Ss to write in combination with relevant topics and opinions, and to talk about their eating habits.1. Guide students to analyze and understand the reading discourse from the aspects of theme content, writing structure, language expression, etc.2. Enable them to write in combination with relevant topics and opinions, and to talk about their eating habits.3. Guide the students to use the cohesive words correctly, strengthen the textual cohesion, and make the expression fluent and the thinking clear.Step1: Warming upbrainstorm some healthy eating habits.1.Eat slowly.2.Don’t eat too much fat or sugar.3.Eat healthy food.4.Have a balanced diet.Step2: Read the passage and then sum up the main idea of each paragraph.
The theme of this section is to express people's views on studying abroad. With the continuous development of Chinese economic construction, especially the general improvement of people's living standards, the number of Chinese students studying abroad at their own expense is on the rise. Many students and parents turn their attention to the world and regard studying abroad as an effective way to improve their quality, broaden their horizons and master the world's advanced scientific knowledge, which is very important for the fever of going abroad. Studying abroad is also an important decision made by a family for their children. Therefore, it is of great social significance to discuss this issue. The theme of this section is the column discussion in the newspaper: the advantages and disadvantages of studying abroad. The discourse is about two parents' contribution letters on this issue. They respectively express their own positions. One thinks that the disadvantages outweigh the advantages, and the other thinks that the advantages outweigh the disadvantages. The two parents' arguments are well founded and logical. It is worth noting that the two authors do not express their views on studying abroad from an individual point of view, but from a national or even global point of view. These two articles have the characteristics of both letters and argumentative essays1.Guide the students to read these two articles, and understand the author's point of view and argument ideas2.Help the students to summarize the structure and writing methods of argumentative writing, and guides students to correctly understand the advantages and disadvantages of studying abroad3.Cultivate students' ability to analyze problems objectively, comprehensively and deeply