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1、焦作市第二十五中学杨艳丽变化的鱼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第3节变化的鱼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yx纵坐标保持不变,将各坐标的横坐标加3则坐标变化为原图形被向右平移3个单位(x,y)(0,0)(5,4)(3,0)(5,1)(5,-
2、1)(3,0)(4,-2)(0,0)(x+3,y)(3,0)(8,4)(6,0)(8,1)(8,-1)(6,0)(7,-2)(3,0)图形有什么变化吗?(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x+2,y+2)(2,2)(7,6)(5,2)(7,3)(7,1)(5,2)(6,0)(2,2)布置任务:将上面鱼的顶点(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)进行如下变化:1、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?2、横坐标保持不变,将各坐标的纵坐标都加2
3、,则原图型变为什么样?3、横坐标保持不变,将各坐标的纵坐标都减2,则原图型变为什么样?4、横坐标分别加2,纵坐标分别加2,所得到的鱼与原来的鱼相比又有什么变化呢?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,
4、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2,则原图型变为什么样?yx猜一猜原图形被向下平移2个单位123456780–1–2–3–4–512349105yx将原来的鱼的顶点的横坐标分别加2,纵坐标分别加2,所得到的鱼与原来的鱼相比又有什么变化呢?想一想
5、123456780–1–2–3–4–512349105yx图中蓝色的鱼是由红色的鱼与怎样变化而得到的?(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x′,y′)它们对应顶点的坐标有什么样的关系?蓝色鱼的坐标是:(3,-2)(8,2)(6,-2)(8,-1)(8,-3)(6,-2)(7,-4)(3,-2)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
6、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
7、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)(0,0)(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)–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,
8、那么所得图案又会发生什么