资源描述
,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,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,*,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,*,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,*,二次函数 的图像和性质,22.1,二次函数的图像和性质22.1.3第2课时,y=a(x,-,h),2,二次函数,知识回顾,二次函数,y=ax,2,和,y=ax,2,+k,的图象是一条抛物线。,1.,二次函数,y=ax,2,和,y=ax,2,+k,的图象是什么形状?,2.,二次函数,y=ax,2,和,y=ax,2,+k,的性质是什么?,向,上,对,称,轴,顶点,坐标,对称轴左,侧,y,随,x,增,大而减小,,对称轴右,侧,y,随,x,增,大而增大,;,开口方向,Y,轴,(,0,,,0,),a,0,a,0,对称轴左,侧,y,随,x,增,大而增大,,对称轴右,侧,y,随,x,增,大而减小,。,解析式,y=ax,2,a0,y=ax,2,+k,a0,向,下,函数的增减性,a,0,a,0,(,0,,,k,),知识回顾二次函数y=ax2和y=ax2+k的图象是一条抛物线,探索新知:,例2,在同一直角坐标系中画出二次函数,的图象,解:列表得:,x,y,O,2,2,2,4,6,4,4,x,-3,-2,-1,0,1,2,3,2,0,2,8,4.5,8,4.5,2,0,2,0.5,0.5,0.5,0.5,4.5,2,0.5,0,0.5,2,4.5,如图所示:,探索新知:例2在同一直角坐标系中画出二次函数,探索新知,抛物线,开口方向,对称轴,顶点坐标,(1,0),(0,0),(,-,1,0),直线,x=-1,y,轴,(x=0),直线,x=1,向,下,x,y,O,2,2,2,4,6,4,4,x=-1,x=1,探索新知抛物线开口方向对称轴顶点坐标(1,0)(0,0),探索新知,观察抛物线 与抛物线 图像,完成以下填空,.,x,y,O,2,2,2,4,6,4,4,以上三条抛物线的形状,位置,.,相同,不同,抛物线 向,平移,个单位后得到,向,平移,个单位后得到,抛物线 向,平移,个单位后得到,左,右,1,1,右,2,(,x,左加右减),探索新知观察抛物线,探索新知:,二次函数y=a(x-h),2,的性质,(,1,)开口方向:,当,a,0,时,开口向上,;,当,a,0,时,开口向下;,(,2,)对称轴:,直线,x=h;,(,3,)顶点坐标:,(,h,,,0,),(,4,)函数的增减性:,当,a,0,时,,对称轴左侧,(x,h,时,)y,随,x,增大而减小,,对称轴右侧,(x,h,时,)y,随,x,增大而增大;,当,a,0,时,,对称轴左侧,y,随,x,增大而增大,,对称轴右侧,y,随,x,增大而减小。,(,5,)最值,若,a,0,,当,x=h,时,,y,有最小值,最小值为,0,若,a,0,,当,x=h,时,,y,有最大值,最大值为,0,探索新知:二次函数y=a(x-h)2的性质(1)开口方向:当,抛物线,开口方向,对称轴,顶点坐标,(1,0),(0,0),(,-,1,0),直线,x=-1,y,轴,(x=0),直线,x=1,向,下,x,y,O,2,2,2,4,6,4,4,x=-1,x=1,抛物线开口方向对称轴顶点坐标(1,0)(0,0)(-1,探索新知:,二次函数y=a(x-h),2,平移规律,(-h,0),(0,0),(h,0),(左加右减),向左平移,h,个单位,向右平移,h,个单位,向右平移,h,个单位,向右平移,2h,个单位,向左平移,2h,个单位,向左平移,h,个单位,探索新知:二次函数y=a(x-h)2平移规律(-h,0)(0,课堂讲练,【例,2,抛物线,y=(x-1),2,的开口 ,对称轴是 ,顶点坐标是 ,它可以看作是由抛物线,y=x,2,向 平移 个单位得到的,.,向上,直线,x=1,(1,,,0),右,1,学导练,P23,例,3,课堂讲练【例2抛物线y=(x-1)2的开口 ,对称,2.,填写下表:,作业,1.,已知二次函数,y=-x,2,+4.,(1),当,x,为何值时,,y,随,x,的增大而减小?,(,2),当,x,为何值时,,y,随,x,的增大而增大?,(3),当,x,为何值时,,y,有最大值?最大值为多少?,(,4,)求图象与,x,轴、,y,轴的交点坐标。,2.填写下表:作业1.已知二次函数y=-x2+4.,巩固练习,抛物线,开口方向,对称轴,顶点坐标,y=2(x+3),2,y=7(x-8),2,y=-3(x-1),2,y=-(x+6),2,向
展开阅读全文