1.设y=x^2-6x+1=0两根为(x1,0)(x2,0),曲线与y轴交点为(0,1)x1=3-2根号2 x2=3+2根号2设圆心为(x3,y3)显然圆心在(x1,0)(x2,0)的中线上x3=(x1+x2)/2=3圆心到(0,1)的距离=圆心到(3+2根号2,0)的距离=>(3)^2+(y3-1)^2=(2根...