图形的变换与坐标.ppt

变化的鱼——图形的变换与坐标横江中学陈勇余在直角坐标系中描出下列各组点，并将各点用线段依次连接起来：(0,1)、(4,4)、(2,1)、(4,2)、(4,0)、(2,1)、(3,-1)、(0,1)x45250114021303220401051y06xy-1-213-1-2(x,y)(0,1)(4,4)(2,1)(4,2)(4,0)(2,1)(3,-1)(0,1)(x+3,y)(3,1)(7,4)(5,1)(7,2)(7,0)(5,1)(7,-1)(3,1)横坐标+3，纵坐标不变。表示为：(x,y)?(x+3,y)向右平移了3个单位长度。横坐标不变，纵坐标分别-2。表示为：(x,y)?(x,y-2)xy-13-212345-1-2-3(0,1)(3,-1)(2,1)(4,0)(4,2)(2,1)(4,4)(0,1)(0,-1)(3,-3)(2,-1)(4,-2)(4,0)(2,-1)(4,2)(0,-1)(x,y-2)向下平移了2个单位长度横坐标+3，纵坐标分别-1。表示为：(x,y)?(x+3,y-2)(0,1)(3,-1)(2,1)(4,0)(4,2)(2,1)(4,4)(0,1)(3,-1)(6,-3)(5,-1)(7,-2)(7,0)(5,-1)(7,2)(3,-1)(x+3,y-1)xy-1-22-1-2-3向右平移了3个单位长度，向下平移了2个单位长度01(x,y)?(x+a,y+b)02沿x轴方向平移a个单位:03若a0,则向右平移；若a0,则向左平移；04沿y轴方向平移b个单位:05若b0,则向上平移；若b0,则向下平移。平移：yx0241-135-212345-2-1-5-4-3(0,1)(3,-1)(2,1)(4,0)(4,2)(2,1)(4,4)(0,1)(0,1)(-3,-1)(-2,1)(-4,0)(-4,2)(-2,1)(-4,4)(0,1)(-x,y)横坐标×(-1)，纵坐标不变。表示为：(x,y)?(-x,y)关于y轴轴对称。(0,1)(3,-1)(2,1)(4,0)(4,2)(2,1)(4,4)(0,1)(0,-1)(-3,1)(2,-1)(4,0)(4,-2)(2,-1)(4,-4)(0,-1)(x,-y)横坐标不变，纵坐标×(-1)。表示为：(x,y)?(x,-y)yx0241-135-212345-2-1-5-4-3-3-4-5关于x轴轴对称。横坐标×(-1)，纵坐标×(-1)。表示为：(x,y)?(-x,-y)(0,1)(3,-1)(2,1)(4,0)(4,2)(2,1)(4,4)(0,1)(0,-1)(-3,-1)(-2,-1)(-4,0)(-4,-2)(-2,-1)(-4,-4)(0,-1)(-x,-y)yx0241-135-212345-2-1-5-4-3-3-4-5关于原点中心对称。(x,y)?(x,-y)01关于x轴对称；02(x,y)?(-x,-y)03关于原点对称。04(x,y)?(-x,y)关于y轴对称；05对称：(0,1)(3,-1)(2,1)(4,0)(4,2)(2,1)(4,4)(0,1)(0,1)(6,-1)(4,1)(8,0)(8,2)(4,1)(8,4)(0,1)(2x,y)横坐标分别×2，纵坐标不变。表示为：(x,y)?(2x,y)yx02416-1357-2123456788-2-1整条鱼沿x轴的方向被拉长为原来的2倍。(x,y)(0,1)(4,4)(2,1)(4,2)(4,0)(2,1)(3,-1)(0,1)(x,2y)(0,2)(4,8)(2,2)(4,4)(4,0)(2,2)(3,-2)(0,2)横坐标不变，纵坐标分别×2。表示为：(x,y)?(x,2y)yx02416-1357-2123456788-2-1整条鱼沿y轴的方向被拉长为原来的2倍