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1、第五章位置的确定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。yx第3节变化的鱼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.yx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
2、不变,将各坐标的横坐标变成原来的2倍会得到什么?则坐标变化为:原图形被横向拉伸2倍(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(2x,y)(0,0)(10,4)(6,0)(10,1)(10,-1)(6,0)(8,-2)(0,0)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?则坐标变化为:yx原图形被横向压缩1/2(x,y)(0,
3、0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x/2,y)(0,0)(2.5,4)(1.5,0)(2.5,1)(2.5,-1)(1.5,0)(2,-2)(0,0)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化为纵坐标保持不变,将各坐标的横坐标加2又会怎样?yx原图形被横向(向右)平移2个单位(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x+2,y)
4、(2,0)(7,4)(5,0)(7,1)(7,-1)(5,0)(6,-2)(2,0)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化为:纵坐标保持不变,将各坐标的横坐标减2,图案会变成什么样?yx-1-2猜一猜原图形被向左平移2个单位(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)123
5、45-1-2-30–1–2–3–4–51234-4-55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yx想一想与原图形关于y轴对称将各坐标的纵坐标保持不变,横坐标都乘以-1,图形会变成什么样?则坐标变化为(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(-x,y)(0,0)(-5,4)(-3,0)(-5,1)(-5,-1)(-3,0)(-2,-2)(0,0)–4123456780–1–2–361234578910xy图中的鱼是将坐标为:(0,0)
6、(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?猜一猜原图形被纵向拉伸2倍–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?猜一猜原图形被纵向压缩1/2123456780–1–2–3–4–512345图中的鱼是将坐标为:(0,0)(5,4)(3,0)
7、(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加2,则原图型变为什么样?yx猜一猜原图形被纵向(向上)平移2个单位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减1,则原图型变为什么样?yx猜一猜原图形被向下平移1个单位123456780–1–2–3–4–512345图中的鱼是将坐标为:(