实际问题与二次函数教学ppt课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,26.3,实际问题与二次函数,(3),26.3 实际问题与二次函数(3),解一,解二,解三,探究,3,图中是抛物线形拱桥，当水面在 时，拱顶离水面,2m,，水面宽,4m,，水面下降,1m,时，水面宽度增加了多少？,继续,解一解二解三探究3 图中是抛物线形拱桥，当水面在,解一,以抛物线的顶点为原点，以抛物线的对称轴为 轴，建立平面直角坐标系，如图所示,.,可设这条抛物线所表示的二次函数的解析式为,:,当拱桥离水面,2m,时,水面宽,4m,即抛物线过点,(2,-2),这条抛物线所表示的二次函数为,:,当水面下降,1m,时,水面的纵坐标为,y=-3,这时有,:,当水面下降,1m,时,水面宽度增加了,返回,解一 以抛物线的顶点为原点，以抛物线的对称轴为 轴，建,解二,如图所示,以抛物线和水面的两个交点的连线为,x,轴，以抛物线的对称轴为,y,轴，建立平面直角坐标系,.,当拱桥离水面,2m,时,水面宽,4m,即,:,抛物线过点,(2,0),这条抛物线所表示的二次函数为,:,当水面下降,1m,时,水面的纵坐标为,y=-1,这时有,:,当水面下降,1m,时,水面宽度增加了,可设这条抛物线所表示的二次函数的解析式为,:,此时,抛物线的顶点为,(0,2),返回,解二如图所示,以抛物线和水面的两个交点的连线为x轴，以抛物线,解三,如图所示,以抛物线和水面的两个交点的连线为,x,轴，以其中的一个交点,(,如左边的点,),为原点，建立平面直角坐标系,.,可设这条抛物线所表示的二次函数的解析式为,:,抛物线过点,(0,0),这条抛物线所表示的二次函数为,:,当水面下降,1m,时,水面的纵坐标为,y=-1,这时有,:,当水面下降,1m,时,水面宽度增加了,此时,抛物线的顶点为,(2,2),这时水面的宽度为,:,返回,解三 如图所示,以抛物线和水面的两个交点的连线为x轴，,例,:,某工厂大门是一抛物线形的水泥建筑物,大门底部宽,AB=4m,顶部,C,离地面的高度为,4.4m,现有载满货物的汽车欲通过大门,货物顶部距地面,2.7m,装货宽度为,2.4m.,这辆汽车能否顺利通过大门,?,若能,请你通过计算加以说明,;,若不能,请简要说明理由,.,例:某工厂大门是一抛物线形的水泥建筑物,大门底,解：如图，以,AB,所在的直线为,x,轴，以,AB,的垂直平分线为,y,轴，建立平面直角坐标系,.,AB=4,A(-2,0) B(2,0),OC=4.4,C(0,4.4),设抛物线所表示的二次函数为,抛物线过,A(-2,0),抛物线所表示的二次函数为,汽车能顺利经过大门,.,解：如图，以AB所在的直线为x轴，以AB的垂直平分线为y轴，,小结,一般步骤,:,(1).,建立适当的直角系,并将已知条件转化为点的坐标,(2).,合理地设出所求的函数的表达式,并代入已知条件或点的坐标,求出关系式,(3).,利用关系式求解实际问题,.,小结一般步骤: (1).建立适当的直角系,并将已知条件,2.,一场篮球赛中,球员甲跳起投篮,如图,2,已知球在,A,处出手时离地面,20/9 m,与篮筐中心,C,的水平距离是,7m,当球运行的水平距离是,4 m,时,达到最大高度,4m,（,B,处）,设篮球运行的路线为抛物线,.,篮筐距地面,3m. ,问此球能否投中,?,1.,有一辆载有长方体体状集装箱的货车要想通过洞拱横截面为抛物线的隧道，如图,1,，已知沿底部宽,AB,为,4m,，高,OC,为,3.2m,；集装箱的宽与车的宽相同都是,2.4m,；集装箱顶部离地面,2.1m,。该车能通过隧道吗？请说明理由,.,(,选做,),此时对方球员乙前来盖帽,已知乙跳起后摸到的最大高度为,3.19m,他如何做才能盖帽成功,?,作业,:,2.一场篮球赛中,球员甲跳起投篮,如图2,新课标北师大版课件系列,高中英语,必修,2,新课标北师大版课件系列高中英语,实际问题与二次函数教学ppt课件,Beijing Opera,the,National,Treasure,Beijing Operathe,Beijing Opera,dates back,to the 18th century.,It is a,combination,of acting, talking, singing, music, dancing and,acrobatics,.,The,costumes,are always in bright colour.,实际问题与二次函数教学ppt课件,实际问题与二次函数教学ppt课件,costume,costume,date back,combination,a national treasure,a piercing voice,acrobatics,costume,a mixture of two or more things,the clothes worn in plays or films,to have a history of,a group of valuable things,very special or important for the country,movement of ones body using the skills of an acrobat,a very high and loud voice,date back,Task 1:,Listen to an interview about Beijing Opera and answer the following questions.,When did Beijing Opera start?,What skills do Beijing Opera actors need to have?,3. How many main roles are there in Beijing Opera?,4. Match the main roles with their names.,sheng male roles with brightly painted faces,dan female roles,jing clown roles,chou male roles,Task 1:,When did Beijing Opera start?,It,dates back,to the late 18,th,century.,What skills do Beijing Opera actors need to have?,It is,a combination of,acting, talking, singing, music, dancing and,acrobatics,.,How many main roles are there in Beijing Opera?,There are four.,When did Beijing Opera start?,4. Match the main roles with their names.,sheng male roles,dan female roles,jing male roles with brightly painted faces,chou clown roles,4. Match the main roles with,sheng,sheng,dan,dan,jing,jing,chou,chou,Beijing Opera,history,main roles,skills needed,Beijing Operahistorymain roles,Task 2:,Listen and use the Strategies to answer the questions.,Where was Beijing Opera performed at the beginning?,2. Why does it have very loud music and a piercing singing style?,3. Why do performers wear brightly coloured costumes?,Task 2:,Where was Beijing Opera performed at the beginning?,It was performed mostly on open-air stages in markets, streets, teahouses or temple courtyards.,2. Why does it have very loud music and a piercing singing style?,In order to be heard over the crowds.,3. Why do performers wear brightly coloured costumes?,In order to be seen by the crowds clearly.,Where was Beijing Opera perfor,Beijing Opera,history,main roles,skills needed,costume,singing,Beijing Operahistorymain roles,Qionghua Cantonese Opera Festival,Qionghua Cantonese Opera Festi,Read the passage about Cantonese Opera carefully and find out information according to the,diagram,.,2. Discuss with your group members to find out the similarities and differences between Beijing Opera and Cantonese Opera.,Read the passage about Cantone,Cantonese Opera,history,main roles,skills needed,costume,singing,Cantonese Operahistorymain rol,Besides Beijing Opera, there are still other National Treasures in China. They serve as a window of China. And through this window, foreigners are able to understand Chinese culture better.,Besides Beijing Opera, there a,Besides Beijing Opera, there are still other National Treasures in China. They serve as a window of China. And through this window, foreigners are able to understand Chinese culture better.,Besides Beijing Opera, there a,Beijing Opera,history,main roles,skills needed,costume,singing,Beijing Operahistorymain roles,Various body movements can,represent,actions,riding in a,carriage,riding a horse,holding a,tassel,in his hand,an army of,thousands,four generals,and four soldiers,walking with,a flag on,each side,Various body movements can rid,