圖形的平移第2課時(shí)課件

大戰(zhàn)場(chǎng)初級(jí)中學(xué)馬曉潔3.2圖形的平移（二）第三章圖形的平移與旋轉(zhuǎn)123456780–1–2–3–4–512349105在直角坐標(biāo)系中描出以下各點(diǎn)：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)并用線段依次連接,看一看是什么圖案. yx將這條“魚”向右平移5個(gè)單位，得到新的“魚”，并在下表中填上平移后各對(duì)應(yīng)點(diǎn)的坐標(biāo)原坐標(biāo)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)新坐標(biāo)(5,0)(10,4)(8,0)(10,1)(10,-1)(8,0)(9,-2)(5,0)你發(fā)現(xiàn)對(duì)應(yīng)點(diǎn)的坐標(biāo)之間有什么關(guān)系？縱坐標(biāo)y不變，橫坐標(biāo)x加5原坐標(biāo)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)新坐標(biāo)(-1,0)(4,4)(2,0)(4,1)(4,-1)(2,0)(3,-2)(-1,0)將這條“魚”向左平移1個(gè)單位，得到新的“魚”，并在下表中填上平移后各對(duì)應(yīng)點(diǎn)的坐標(biāo)你發(fā)現(xiàn)對(duì)應(yīng)點(diǎn)的坐標(biāo)之間有什么關(guān)系？縱坐標(biāo)y不變，橫坐標(biāo)x減1將這條“魚”向上平移1個(gè)單位，得到新的“魚”，并在下表中填上平移后各對(duì)應(yīng)點(diǎn)的坐標(biāo)你發(fā)現(xiàn)對(duì)應(yīng)點(diǎn)的坐標(biāo)之間有什么關(guān)系？橫坐標(biāo)y不變，縱坐標(biāo)x加1原坐標(biāo)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)新坐標(biāo)(0,+1)(5,5)(3,1)(5,2)(5,0)(3,1)(4,-1)(0,1)將這條“魚”向下平移3個(gè)單位，得到新的“魚”，并在下表中填上平移后各對(duì)應(yīng)點(diǎn)的坐標(biāo)你發(fā)現(xiàn)對(duì)應(yīng)點(diǎn)的坐標(biāo)之間有什么關(guān)系？橫坐標(biāo)y不變，縱坐標(biāo)x減3原坐標(biāo)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)新坐標(biāo)(0,-3)(5,1)(3,-3)(5,-2)(5,-4)(3,-3)(4,-5)(0,-3)已知：圖形各點(diǎn)的坐標(biāo)，圖形平移的方向和距離。

探求：平移后圖形上各對(duì)應(yīng)點(diǎn)的坐標(biāo)。圖形沿著x軸左右平移，則各點(diǎn)橫坐標(biāo)x變化（右加左減），縱坐標(biāo)y不變圖形沿著y軸上下平移，則各點(diǎn)縱坐標(biāo)y變化（上加下減），橫縱標(biāo)x不變123456780–1–2–3–4–512349105圖中的魚是將坐標(biāo)為：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的點(diǎn)用線段依次連接而成的則坐標(biāo)變化為：

縱坐標(biāo)不變，將各坐標(biāo)的橫坐標(biāo)加２又會(huì)怎樣？yx原圖形被向右平移2個(gè)單位(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x+2,y)(2,0)(7,4)(5,0)(7,1)(7,-1)(5,0)(6,-2)(2,0)123456780–1–2–3–4–512349105圖中的魚是將坐標(biāo)為：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的點(diǎn)用線段依次連接而成的則坐標(biāo)變化為：縱坐標(biāo)保持不變，將各坐標(biāo)的橫坐標(biāo)減２，圖案會(huì)變成什么樣？yx-1-2原圖形被向左平移2個(gè)單位(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x-2,y)(-２,0)(3,4)(1,0)(3,1)(3,-1)(1,0)(2,-2)(-2,0)123456780–1–2–3–4–512349105圖中的魚是將坐標(biāo)為：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的點(diǎn)用線段依次連接而成的則坐標(biāo)變化為：橫坐標(biāo)保持不變，將各坐標(biāo)的縱坐標(biāo)加3，圖案會(huì)變成什么樣？yx-1-2原圖形被向上平移3個(gè)單位(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x,y+3)(0,3)(5,7)(3,3)(5,4)(5,2)(3,3)(4,1)(0,3)123456780–1–2–3–4–512349105圖中的魚是將坐標(biāo)為：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的點(diǎn)用線段依次連接而成的則坐標(biāo)變化為：橫坐標(biāo)保持不變，將各坐標(biāo)的縱坐標(biāo)減2，圖案會(huì)變成什么樣？yx-1-2原圖形被向下平移2個(gè)單位(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x,y-2)(0,-2)(5,2)(3,-2)(5,-1)(5,-3)(3,-2)(4,-4)(0,-2)已知：圖形各點(diǎn)的坐標(biāo)，各點(diǎn)變化后的對(duì)應(yīng)點(diǎn)的坐標(biāo)。

探求：新圖形是如何由原來(lái)的圖形平移得到的（探求圖形平移的方向和距離）。

各點(diǎn)橫坐標(biāo)x變化，則圖形沿著x軸左右平移（加了則向右，減了則向左）各點(diǎn)縱坐標(biāo)y變化,則圖形沿著y軸上下平移(加了則向上，減了則向下）1、一個(gè)圖形沿x軸方向平移a（a>0）個(gè)單位長(zhǎng)度:(x,y)(x+a,y)2、一個(gè)圖形沿y軸方向平移a（a>0）個(gè)單位長(zhǎng)度:向右平移a個(gè)單位向左平移a個(gè)單位(x-a,y)(x,y)(x,y+a)向上平移a個(gè)單位向下平移a個(gè)單位(x,y-a)1.點(diǎn)A（5，4）向上平移2個(gè)單位，則它對(duì)應(yīng)點(diǎn)的坐標(biāo)為______

點(diǎn)B(1，-1)向下平移5個(gè)單位，則它對(duì)應(yīng)點(diǎn)的坐標(biāo)為______點(diǎn)A（5，4）向右平移1個(gè)單位，則它對(duì)應(yīng)點(diǎn)的坐標(biāo)為______

點(diǎn)B(1，-1)向左平移4個(gè)單位，則它對(duì)應(yīng)點(diǎn)的坐標(biāo)為______2.點(diǎn)C（5，4）移動(dòng)后的坐標(biāo)為(5，-1)，則它的移動(dòng)方向_____和距離____

點(diǎn)D(1，-1)移動(dòng)后的坐標(biāo)為(-4，-1)，

則它的移動(dòng)方向_____和距離____

平移小結(jié)1.縱坐標(biāo)不變，橫坐標(biāo)分別增加（減少）a個(gè)單位時(shí)，圖形