Question

已知圆C1：x^2+y^2+2x+2y-2=0,圆C2：x^2+y^2-2ax-2by+a^2-1=0,当a,b变化时,

Answer 1

圆C1：x^2+y^2+2x+2y-2=0,即：(x+1)^2+(y+1)^2=2^2,圆心为（-1,-1）半径r=2.圆C2：x^2+y^2-2ax-2by+a^2-1=0,即：(x-a)^2+(y-b)^2=1-b^2,圆心为（a,b）半径r=√(1-b^2).当a,b变化时,圆C2始终平分圆C1的周长,即：C1与C...