Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,11/7/2009,#,-,#,-,3,.,2,双曲线的简单性质,知识梳理,典型透析,随堂演练,目标导航,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,*,*,1变化的快慢与变化率,1变化的快慢与变化率,第,1,课时,平均变化率,第1课时平均变化率,1,.,理解函数平均变化率的概念,.,2,.,会求给定函数在某个区间上的平均变化率,并能根据函数的平均变化率判断函数在某个区间上的变化快慢,.,1.理解函数平均变化率的概念.,高中数学北师大版选修1-1ppt课件3,名师点拨,1,.,平均变化率是曲线陡峭程度的,“,数量化,”,或者说,曲线陡峭程度是平均变化率的,“,视觉化,”,.,2,.,对于函数,y=f,(,x,),当自变量,x,在,x,0,处有改变量,x,时,函数,y,相应地有改变量,y,则,f,(,x,),从,x,0,到,x,0,+,x,的平均变化率有更一般的形式,:,名师点拨1.平均变化率是曲线陡峭程度的“数量化”,或者说,曲,答案,:,C,答案:C,【做一做,2,】,如果质点,M,按规律,s=,3,+t,2,运动,其中,s,表示路程,t,表示时间,则在一小段时间,2,2,.,1,中相应的平均速度是,(,),A.4B.4,.,1C.0,.,41D.3,答案,:,B,【做一做,3,】,在平均变化率的定义中,自变量,x,在,x,0,处的增量,x,0,.,(,填,“,”“,”,或,“”),答案,:,【做一做2】如果质点M按规律s=3+t2运动,其中s表示路,题型一,题型二,题型三,求平均变化率,【例,1,】,求函数,f,(,x,),=x,2,在,x=,1,2,3,附近的平均变化率,取,x,都为,在哪一点附近平均变化率最大,?,分析,:,利用平均变化率的定义,代入定义式即可求得,.,题型一题型二题型三求平均变化率分析:利用平均变化率的定义,代,题型一,题型二,题型三,题型一题型二题型三,题型一,题型二,题型三,反思,在求平均变化率时,应先求函数值的改变量与自变量的改变量,然后再计算它们的比值,.,题型一题型二题型三反思在求平均变化率时,应先求函数值的改变量,题型一,题型二,题型三,【变式训练,1,】,求函数,y=-,2,x,2,+,3,在区间,2,2,+,x,内的平均变化率,并求当,时平均变化率的值,.,题型一题型二题型三【变式训练1】求函数y=-2x2+3在区,题型一,题型二,题型三,平均变化率在物理中的应用,【例,2,】,一辆汽车按,s=,3,t,2,+,1,做直线运动,求这辆车从,3 s,到,6 s,的平均速度,(,位移单位,:m,时间单位,:s),.,分析,:,求平均速度就是把位移,s,看成时间,t,的函数,利用求平均变化率的公式来求平均速度,.,反思,求解平均速度方法就是把位移,s,看成时间,t,的函数,进而求出,s,(,t,1,),s,(,t,2,),.,题型一题型二题型三平均变化率在物理中的应用反思求解平均速度方,题型一,题型二,题型三,【变式训练,2,】,例,2,中,若将,“,从,3 s,到,6 s,的平均速度,”,改为,“,在区间,3,3,+,t,上的平均速度,”,则求当,时平均速度的值,.,解,:,s,(3,+,t,),=,3(3,+,t,),2,+,1,=,39,+,6,t+,(,t,),2,+,1,=,3(,t,),2,+,18,t+,28m,s,(3),=,3,3,2,+,1,=,28(m),.,s,(3,+,t,),-s,(3),=,(3(,t,),2,+,18,t,)m,.,题型一题型二题型三【变式训练2】例2中,若将“从3 s到6,题型一,题型二,题型三,易错辨析,易错点,不理解平均变化率的概念而致误,题型一题型二题型三易错辨析,1,2,3,4,5,1.,某物体的位移公式为,s=s,(,t,),从,t,0,到,t,0,+,t,这段时间内,下列理解正确的是,(,),A.(,t,0,+,t,),-t,0,称为函数值增量,B.,t,0,称为函数值增量,C.,s=s,(,t,0,+,t,),-s,(,t,0,),称为函数值增量,解析,:,函数值增量的概念是指函数值的改变量,.,答案,:,C,123451.某物体的位移公式为s=s(t),从t0到t0+,1,2,3,4,5,2.,一物体的运动方程是,s=,2,t,2,其中,s,表示路程,t,表示时间,则从,2 s,到,(2,+,t,)s,这段时间内位移的增量,s,为,(,),A.8B.8,+,2,t,C.8,t+,2(,t,),2,D.4,t+,2(,t,),2,解析,:,s=,2(2,+,t,),2,-,2,2,2,=,8,t+,2(,t,),2,.,答案,:,C,123452.一物体的运动方程是s=2t2,其中s表示路程,1,2,3,4,5,12345,1,2,3,4,5,答案,:,29,.,89,m/s,12345答案:29.89 m/s,1,2,3,4,5,5.,甲、乙两厂污水的排放量,W,与时间,t,的关系如图,试指出哪一个厂治污效果较好,.,解,:,在,t,0,处,虽然,W,1,(,t,0,),=W,2,(,t,0,),所以,在相同的变化时间,t,内,甲厂比乙厂的平均治污率小,.,所以乙厂治污效果较好,.,123455.甲、乙两厂污水的排放量W与时间t的关系如图,试,团Tiffany，a 16yearold girl，was very shy.Last September，her best frien“I was really sad the moment I heard the bad news and I didnt know what to do，”Tiffany recalled.“I shut myself in my room for a whole week.It was then that my aunt took me to a sports club one Saturday and I saw so many young people playing different kinds of sports there.I signed up for a beginners course in volleyball and since then I have been playing this sport.Now I practice twice a week there.It is wonderful playing sports in this club and I have made lots of friends as well.2 ”,The most basic aim of playing sports is that you can improve your health even if you are not very good at sports.Besides，you can get to know a circle of people at your age while playing sports.3 Since she joined the sports club，s,I got used to the life here.And now I know lots of(5)_ here.For example,when I meet my friend on the street,I usually(6)_ him like this,“Hey,where are you going?”In our country if someone asks this,people may get(7)_ but in this country people wont.Of course,there are some other interesting things here.Ill tell you about them next time.,he has opened up herself and now she has become very active and enjoys meeting and talking with others.,1Its polite for girls to kiss each other on the side of the face.s also become more confident.团圆圆一家在台湾可受欢迎了。每天，小朋友们排着长队，等着跟它们合影留念。从“排着长队”体现出每天喜欢它们的人不计其数，特别受选D.A.根据同类项合并法则,与不是同类项,不能合并,故本选项错误;B.根据算术平方根的定义,=3,故本选项错误;C.根据同底数幂的乘法aa2=a3,故本选项错误;D.根据积的乘方,(2a3)2=4a6,故本选项正确.欢迎。从“合影留念”体现出大家都想和大熊猫留住最美丽的瞬间以作纪念。,Nothing can be accomplished without norms or standards.,精品资料！感谢阅读下载！,团Tiffany，a 16yearold girl，wa,