A. -2

B. -12

C. -3

D. 1

The equation of the circle cutting orthogonally the circles x^{2}+y^{2}-8x-2y+16=0, x^{2}+y^{2}-4x-4y-1=0 and passing through the point (1, 1) is

If x^{2}+y^{2}+2gx+2fy+9=0 represents a circle with centre (1, -3) then radius=

The number of common tangents to the two circles x^{2}+y^{2}-8x+2y=0 and x^{2}+y^{2}-2x-16y+25=0 is

From any point on the circle x^{2}+y^{2}=a^{2} tangents are drawn to the circle x^{2}+y^{2}=a^{2} sin^{2}θ. The angle between them is

If the tangent at P on the circle x^{2}+y^{2}=a^{2} cuts two parallel tangents of the circle at A and B then PA. PB=