Question

求圆心在直线X-Y-4=0上,并且经过圆X2+Y2+6X-4=0与X2+Y2+6y-28=0交点的圆的方程

Answer 1

X2+Y2+6X-4=0与X2+Y2+6y-28=0联立

(-1,3),(-6,-2)

圆心在直线X-Y-4=0上,(x-a)^2+(x-a+4)^2=r^2

(a+1)^2+(a-7)^2=r^2

(a+6)^2+(a-2)^2=r^2

联立,a=1/2,r^2=44.5

圆的方程(x-0.5)^2+(y+3.5)^2=44.5