Question

已知圆C:x^2+y^2-6x-8y+21=0,点A(1,0),O是坐标原点 若以A(1

Answer 1

圆C:(x-3)²+(y-4)²=4

C(3,4)

A:(x-1)²+y²=r²

|AC|=√((3-1)²+(4-0)²)=2√5

AC垂直平分MN于B,MB=√2

|AC|=√(AM²-MB²)+√(CM²-MB²)

2√5=√(r²-2)+√(2²-2)

√(r²-2)=2√5-√2

r²-2=20+2-4√10

r²=24-4√10

圆A：(x-1)²+y²=24-4√10