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1、單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,第二級(jí),第三級(jí),第四級(jí),第五級(jí),*,單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,第二級(jí),第三級(jí),第四級(jí),第五級(jí),*,二次函數(shù),y=a(x-h),2,的圖象和性質(zhì),你說(shuō)我說(shuō)大家說(shuō),1,、,說(shuō)出下列二次函數(shù)的開(kāi)口方向、對(duì)稱(chēng)軸及頂點(diǎn)坐標(biāo),(1),(2),(3),學(xué)習(xí)目標(biāo),1,會(huì)畫(huà)二次函數(shù),y,a,(,x-h,),2,的圖象,并掌握它的開(kāi)口方向、對(duì)稱(chēng)軸、頂點(diǎn)坐標(biāo)及增減性等性質(zhì)。,2,掌握二次函數(shù),y,a,(,x-h,),2,圖象的平移規(guī)律,.,1,、自學(xué)內(nèi)容:,P,33,“探究”,P,34,的內(nèi)容。,2,、自學(xué)時(shí)間:,8,分鐘,3,、自學(xué)檢測(cè)
2、,:,完成導(dǎo)學(xué)稿前置性自學(xué)第,2,、,3,題,自學(xué)指導(dǎo),x,-4,-3,-2,-1,0,1,2,1,、分別,列表,2,、描點(diǎn),3,、連線(xiàn),畫(huà)出二次函數(shù) 的圖象,1,2,3,4,5,x,-1,-2,-3,-4,-5,-6,-7,-8,-9,1,y,o,-1,-2,-3,-4,-5,-10,-4.5,0,-0.5,-2,-2,-4.5,直線(xiàn),x=,1,直線(xiàn),x=1,x,-2,-1,0,1,2,3,4,-0.5,-4.5,-2,-0.5,0,-0.5,-2,-4.5,函數(shù),開(kāi)口方向,頂點(diǎn),對(duì)稱(chēng)軸,最值,增減性,當(dāng),x=,時(shí),,y,有最,值是,。,當(dāng),x,時(shí),y,隨,x,的增大而增大;,當(dāng),x,時(shí),y
3、,隨,x,的增大而減小,當(dāng),x=,時(shí),,y,有最,值是,。,當(dāng),x,時(shí),y,隨,x,的增大而,增大,;,當(dāng),x,時(shí),y,隨,x,的增大而減小,向,下,向,下,(,-1,,,0,),(,1,,,0,),-1,大,0,1,大,0,-1,直線(xiàn),X=-1,直線(xiàn),X=1,-1,1,1,開(kāi)口方向,頂點(diǎn)坐標(biāo),對(duì)稱(chēng)軸,最值,增減性,a,0,當(dāng),x=,時(shí),,y,有最,值是,.,在對(duì)稱(chēng)軸的左側(cè),,,y,隨,x,的增大而,;,在對(duì)稱(chēng)軸的右側(cè),,,y,隨,x,的增大而,.,a,0,當(dāng),x=,時(shí),,y,有最,值是,。,在對(duì)稱(chēng)軸左側(cè),,,y,隨,x,的增大而,;,在對(duì)稱(chēng)軸右側(cè),,,y,隨,x,的增大而,。,1,、二次函數(shù)
4、,y=a,(,x-,),2,的性質(zhì),探究,向,下,向,上,(,h,,,0,),(,h,,,0,),直線(xiàn),X=h,直線(xiàn),X=h,h,h,小,大,0,0,減小,增大,增大,減小,1,2,3,4,5,x,-1,-2,-3,-4,-5,-6,-7,-8,-9,1,y,o,-1,-2,-3,-4,-5,-10,探究,思考:,1,、拋物線(xiàn) ,,與拋物線(xiàn) 有什么關(guān)系,?,1,2,3,4,5,x,-1,-2,-3,-4,-5,-6,-7,-8,-9,1,y,o,-1,-2,-3,-4,-5,-10,向,左,平移,1,個(gè)單位長(zhǎng)度,向,右,平移,1,個(gè)單位長(zhǎng)度,2,、討論拋物線(xiàn),y=a(x,h),2,與拋物線(xiàn),y
5、=ax,2,的關(guān)系?,探究,1,、拋物線(xiàn),y=a(x,h),2,與,y=ax,2,形狀相同,位置不同。,2,、拋物線(xiàn),y=a(x,h),2,可以由拋物線(xiàn),y=ax,2,向左或向右平移得到:,h0,,向右平移,h,個(gè)單位長(zhǎng)度得到,;h0,,向左平移|,h,|,個(gè)單位長(zhǎng)度得到。,簡(jiǎn)記為:左加右減,歸納,拋物線(xiàn),y=a(x,h),2,與拋物線(xiàn),y=ax,2,的關(guān)系:,想一想,我能行!,1,、拋物線(xiàn),y=(x+1),2,的開(kāi)口向,,對(duì)稱(chēng)軸是,,頂點(diǎn)坐標(biāo)是,。,2,、,函數(shù),y=5(x3),2,當(dāng),x,時(shí),,y,隨,x,的增大而增大,當(dāng),x,時(shí),y,隨,x,的增大而減小。,3,、,拋物線(xiàn),y=-2x,2
6、,向下平移,2,個(gè)單位長(zhǎng)度得到拋物線(xiàn),,若將拋物線(xiàn),y=-2x,2,向左平移,2,個(gè),單位長(zhǎng)度得到拋物線(xiàn),。,下,直線(xiàn),x,=1,(1,,,0),3,3,y=-2x,2,-2,y=-2(x+2),2,4,、若,y=a(x+1),2,經(jīng)過(guò)點(diǎn)(,1,4,),則,a,=,拋物線(xiàn)的開(kāi)口方向,。,5,、拋物線(xiàn),y=x,2,-2x+1,的頂點(diǎn)坐標(biāo)是,。,1,向上,(,1,,,0,),練一練,我更棒!,6,、拋物線(xiàn),y=a(x+h),2,的對(duì)稱(chēng)軸為直線(xiàn),x=3,且該拋物線(xiàn)與拋物線(xiàn),y=-2x,2,的形狀相同,開(kāi)口方向相同,則,h=,a=,。,7,、已知拋物線(xiàn),y=a(x,h),2,的對(duì)稱(chēng)軸為直線(xiàn),x=-2,
7、且過(guò)點(diǎn)(,1,,,-3,),(1),求拋物線(xiàn)的解析式,(2),若將,(1),中拋物線(xiàn)向右平移,3,個(gè)單位長(zhǎng)度,寫(xiě)出平移后的拋物線(xiàn)的解析式。,-3,-2,1.,拋物線(xiàn),y=-3(x+2),2,開(kāi)口向,,對(duì)稱(chēng)軸為,,頂點(diǎn)坐標(biāo)為,.,2.,將拋物線(xiàn),y=-2x,2,向左平移一個(gè)單位長(zhǎng)度,再向右平移,3,個(gè)單位長(zhǎng)度得拋物線(xiàn)解析式為,.,3.,拋物線(xiàn),y=3(x-8),2,最小值為,.,4.,寫(xiě)出一個(gè)開(kāi)口向上,對(duì)稱(chēng)軸為,x=-2,的拋物線(xiàn)解析式為,.,5,.,將拋物線(xiàn),y=ax,2,向左平移后所得新拋物線(xiàn)的頂點(diǎn)的橫坐標(biāo)為,-2,,并且新拋物線(xiàn)經(jīng)過(guò)點(diǎn)(,1,,,3,),求,a,的值,下,直線(xiàn),X=-2,(
8、-2,0),y=2(x+2),2,達(dá)標(biāo)檢測(cè),y=-2(x 2),2,0,1,、本節(jié)課你有哪些收獲?,2,、你認(rèn)為今天這節(jié)課最需要掌握的是,?,今天我的收獲,開(kāi)口方向,頂點(diǎn)坐標(biāo),對(duì)稱(chēng)軸,最值,增減性,a,0,當(dāng),x=,時(shí),,y,有最,值是,.,在對(duì)稱(chēng)軸左側(cè),,y,隨,x,的增大而,;,在對(duì)稱(chēng)軸右側(cè),,y,隨,x,的增大而,。,a,0,當(dāng),x=,時(shí),,y,有最,值是,。,在對(duì)稱(chēng)軸左側(cè),,y,隨,x,的增大而,;,在對(duì)稱(chēng)軸右側(cè),,y,隨,x,的增大而,。,1,、二次函數(shù),y=a,(,x-,),2,的性質(zhì),歸納,向,下,向,上,(,h,,,0,),(,h,,,0,),直線(xiàn),X=h,直線(xiàn),X=h,h,h,小,大,0,0,減小,增大,增大,減小,布置作業(yè),一、必做題,:,課本,p,41,頁(yè)第,5,題(,2,),二、選做題:,二次函數(shù),y=a(x+h),2,(a,0,)的圖象由,向右平移得到,且過(guò)點(diǎn)(,1,-2,),試說(shuō)明向右平移了幾個(gè)單位長(zhǎng)度?,謝謝大家,再見(jiàn),!,