y=4x-x^2=-(x-2)^2+4
顶点坐标为(2,4)对称轴x=2
y=-2x^2+4
顶点坐标为(0,4)对称轴x=0
y=-2x^2+1
顶点坐标为(0,1)对称轴x=0
y=4x-x方得顶点坐标和对称轴 y=-2x方+4的顶点坐标 y=-2x方+1的对称轴
y=4x-x^2=-(x-2)^2+4
顶点坐标为(2,4)对称轴x=2
y=-2x^2+4
顶点坐标为(0,4)对称轴x=0
y=-2x^2+1
顶点坐标为(0,1)对称轴x=0