圆C:x^2+y^2-2x-2y+1=0,即:(x-1)^2+(y-1)^2=1,圆心位于（1,1）将直线l:y=kx代入得：(k^2+1)x^2-2(k+1)x+1=0有两个根,要求△=4(k+1)^2-4(k^2+1)=8k>0x1+x2=2(k+1)/(k^2+1)………………①x1*x2=1/(k^2+1)………………...