A. 0
B. k≥1/2
C. -1/2≤k≤1/2
D. k≤1/2
The locus of the point of intersection of two tangents drawn to the circle x2+y2=a2 which make a constant angle α to each other is
The straight line x-2y+1=0intersects the line circle x2+y2=25 in points P and Q, the coordinates of the point of intersection of tangents drawn at P and Q to the circle is
If the tangents at (3, -4) to the circle x2+y2-4x+2y-5=0 w.r.t the circle x2+y2+16x+2y+10=0 in A and B, then the midpoint of AB is
The polar of (x1, y1) w.r.t the circle x2+y2=a2 meets the coordinate axes in A and B. The area of ΔOAB is
The equations of the tangents drawn from the origin x2+y2+2gx+2fy+f2=0 is
The area of the triangle formed by the tangents from (1, 3) to the circle x2+y2-4x+6y+1=0 and its chord of contact is
The condition that the pair of tangents drawn from (g, f) to the circle x2+y2+2gx+2fy+c=0 may be at right angles is
The equation of the circle passing through the points of intersection of the circles x2+y2-8x+10y+2=0, x2+y2-3x+5y-1=0 and touching line 2x+y=3 is
The equation of the circle passing the origin having its centre on the line x+y=4 and cutting the circle x2+y2-4x+2y+4=0 orthogonally is
The limiting points of the coaxal system x2+y2+2λx+4=0 are