温故知新123456780–1–2–3–4–512349105在直角坐标系中描出以下各点：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)并用线段依次连接,看一看是什么图案.yxy123456780–1–2–3–4–512349105图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的纵坐标保持不变，将各坐标的横坐标变成原来的2倍会得到什么？123456780–1–2–3–4–512349105图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的纵坐标保持不变，将各坐标的横坐标变成原来的2倍会得到什么？则原坐标变为：(0,0)(10,4)(6,0)(10,1)(10,-1)(6,0)(8,-2)(0,0)yx原图形被横向拉伸2倍(X,Y)----(2X,Y)123456780–1–2–3–4–512349105图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的纵坐标保持不变,将各坐标的横坐标变成原来的1/2，图形会怎么变？则原坐标变为：(0，0)(2.5，4)(1.5，0)(2.5，1)(2.5，-1)(1.5，0)(2，-2)(0，0)yx原图形被横向压缩1/2(X,Y)----(1/2X,Y)123456780–1–2–3–4–512349105图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的则坐标变为(3,0)(8,4)(6,0)(8,1)(8,-1)(6,0)(7,-2)(3,0)纵坐标保持不变,将各坐标的横坐标+3又会怎样？yx原图形被横向（向右）平移3个单位(X,Y)-----(X+3,Y)123456780–1–2–3–4–512349105图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的则坐标变为：(-2,0)(3,4)(1,0)(3,1)(3,-1)(1,0)(2,-2)(-2,0)纵坐标保持不变,将各坐标的横坐标-2,图案会变成什么样？yx-1-2原图形被向左平移2个单位(X,Y)-----(X–2,Y)–4123456780–1–2–361234578910xy图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的如果横坐标保持不变，纵坐标变成原来的2倍，那么所得图案又会发生什么变化?原图形被纵向拉伸2倍(X,Y)----(X,2Y)–4123456780–1–2–361234578910xy图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的如果横坐标保持不变，纵坐标变成原来的½，那么所得图案又会发生什么变化?原图形被纵向压缩1/2(X,Y)----(X,1/2Y)123456780–1–2–3–4–512345图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的横坐标保持不变,将各坐标的纵坐标都+2,则原图型变为什么样？yx原图形被纵向（向上）平移2个单位(X,Y)-(X,Y+2)123456780–1–2–3–4–512345图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的横坐标保持不变,将各坐标的纵坐标都-1,则原图型变为什么样？yx原图形被向下平移1个单位(X,Y)----(X,Y–1)–4123456780–1–2–361234578910xy1.图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)的点用线段依次连接而成的如果横坐标与纵坐标同时乘以2，那么所得图案又会发生什么变化?原坐标变为：(0,0)(10,8)(6,0)(10,2)(10,-2)(6,0)(8,-4)(0,0）原图形被横向、纵向各拉伸2倍原图形的形状没变，面积是原来的4倍。(X,Y)----(2X,2Y)一、平移1.纵坐标不变，横坐标分别增加（减少）a个单位时，图形平移a个单位；2.横坐标不变，纵坐标分别增加（减少）a个单位时，图形平移a个单位；向右（向左）向上（向下）二、伸长（压缩）3.纵坐标不变，横坐标分别变为原来的a倍，图形为原来的a倍（a>1）4.横坐标不变，纵坐标分别变为原来的a倍，图形为原来的a倍（a>1）5.横坐标与纵坐标同时变为原来的a倍，图形为原来的a倍(a>1)…伸长或图形横向缩短为原来的a倍横向(0
