A. 8
B. 4
C. 2
D. 1
If the distances from the origin to the centres of three circles x2+y2-2k, x=c2 (i=1,2,3),are in G.P, then the lengths of the tangents drawn to them from any point on the circle x2 + v2 = c2 are in
If α, β are the roots of x2+ ax+b=0 and γ, δ are the roots y2+cx+d=0 then the equation of the circle having the line joining (α, γ), (β, δ) as diameter is
The least distance of the line 8x-4y+73=0 from the circle 16x2+16y2+48x-8y-43=0 is
The equation of the circle with centre (-1, 1) and touching the circle x2+y2-4x+6y-3=0 externally is
The orthocentre of triangle formed by the lines x + 3y = 10 and 6x<sup>2</sup> + xy - y<sup>2</sup> = 0 is:
B and C are two points on the circle x2+y2=a2. From a point A(b, c) on that circle AB=AC=d. The equation to Bc is
The locus of the centre of the circles which touché both the circles x2+y2=a2 and x2+y2=4ax externally has the equation
The equation of the circle belonging to the coaxal system of which (1, 2)(4, 3) are the limiting points and passing through the origin is
The length of the intercept made by the circle x2+y2+10x-12y-13=0 on y-axis is
The angle between a pair-of tangents drawn from a point P to the circle x2+y2+4x-6y+9sin2α+13cos2 α=0 is 2α.The equation of the locus of the point P is