Question

求过点A(1,4)且与圆M:x^2+y^2-6x-2y+5=0切于点B(1,2)的圆C的方程

Answer 1

M：(x-3)^2+(y-1)^2=5

过点(1,2)、(3,1)的直线方程为y-2=-(1/2)(x-1) x+2y-5=0

设圆心为(-2b+5,b)

(-2b+5-1)^2+(b-2)^2=(-2b+5-1)^2+(b-4)^2 b=3 R^2=5

(x+1)^2+(y-3)^2=5