Given the circle C: (x-1) 2 + (y + 1) 2 = 1, then the distance from the center of the circle C to the origin of the coordinate o is___ ．

Given the circle C: (x-1) 2 + (y + 1) 2 = 1, then the distance from the center of the circle C to the origin of the coordinate o is___ ．

From the circle C: (x-1) 2 + (y + 1) 2 = 1, we can get the center of the circle C (1 -, 1); | OC | = 12 + (- 1) 2 = 2

It is known that the center of the circle is the intersection point of the straight line x + Y-1 = 0 and x-y-3 = 0, and the radius is the distance from the center of the circle to the origin

The intersection of X + Y-1 = 0 and x-y-3 = 0 is (2, - 1)
So the equation of the circle
(x-2)^2+(y+1)^2=5

Line L: x + 2y-1 = 0, circle X & # 178; + Y & # 178; = 16, judge the position relationship between line and circle, if intersecting, calculate the chord length

According to the comparison between the distance from the center of the circle to the straight line and the radius of the circle, the position relationship between the straight line and the far side can be obtained. The root of D = 5 is obtained