1. If there are only two points on the circle (x-3) 2+(y+5) 2 = R2, and the distance to the straight line 4x-3y = 2 is equal to 1, then the range of radius r is

A.(4,6)

B.

D.

2 The equation of a known circle is x2+y2+ax+2y+a2=0, and the fixed point is a (1, 2). To make the crossing point A (1, 2) become two tangents of a circle, find the value range of A. 。

3. (Beijing Spring 2005 1 1) If the circle is X2+Y2+MX-

=0 is tangent to the straight line Y =- 1 and its center is on the left side of the y axis, then the value of m is _ _ _ _ _ _ _ _.