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1、第三节变化的鱼单位：乾县周城初级中学作者：聂亚社012345x-1-21234y-3-4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。原图形被向右平移2个单位yx053214672143-4-3-2-1(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)图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0
2、,0)的点用线段依次连接而成的原图形被向左平移2个单位012432143-1-1-25-2-4-3xy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（或加-2）将会怎样？(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)原图形被向上平移2个单位图中的鱼是将坐标为：(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4
3、,-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加2将会怎样？1023123465x456-2-1y(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x,y+2)(0,2)(5,6)(3,2)(5,3)(5,1)(3,2)(4,0)(0,2)原图形被向下平移2个单位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减2（或加-2）将会怎样？0213546124-1-3-4-2(x,y)(0,0)(5,4)(3
4、,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)3yx规律总结1.纵坐标不变，横坐标分别增加（减少）a个单位时，图形向右（向左）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，图形向上（向下）平移a个单位。原图形被横向拉伸2倍012345678910123-14-3-2-4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，将会怎样
5、？(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)原图形被横向压缩为原来(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x,y)(0,0)(2.5,4)(1.5,0)(2.5,1)(2.5,-1)(1.5,0)(2,-2)(0,0)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
6、来的倍，将会怎样？0132412345-1-2-3-46yx原图形被纵向拉伸2倍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变成原来的2倍，将会怎样？(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(3,0)(4,-2)(0,0)(x,2y)(0,0)(5,8)(3,0)(5,2)(5,-2)(3,0)(4,-4)(0,0)10324657183-142-4-265-3yx原图形被纵向压缩为原来的(x,y)(0,0)(5,4)(3,0)(5,1)(5,-1)(
7、3,0)(4,-2)(0,0)(x,y)(0,0)(5,2)(3,0)(5,0.5)(5,-0.5)(3,0)(4,-1)(0,0)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变成原来的将会怎样？10213423-35-1-24-4yx规律总结1、纵坐标不变，横坐标分别变为原来的a倍，图形横向伸长为原来的a倍（a>1）
