A. 2√7
B. √7
C. 4√7
D. 8√7
The condition that the pair of tangents drawn from the origin to the circle x2+y2+2gx+2fy+c=0 may be at right angles is
The equation of the chord of the circle x2+y2+16x+2y+10=0 parallel to the chord x-3y-15=0 and which is at the same distance from the centre is
If the tangent to the circle x2+y2=5 at (1, -2) also touches the circle x2+y2-8x+6y+20=0, then the point of contact is
The radical centre of the circle x2+y2+arx+br y+c=0, r=1, 2, 3 is
The equation of the circle cutting the circle x2+y2+2x-4y+8=0 orthogonally and coaxial with the circle x2+y2+6x-4y-12=0, x2+y2-4x-6y-12=0 is
The inverse point of (1, -1) with resapect to the circle x2+y2=4 is
The equation of the tangent to the circle x2+y2+2x+2y-7=0 which makes 450 with the x axis is
If OA, OB are two equal chords of the circle x2+y2-2x+4y=0 perpendicular to each other and passing through the origin, then the equations of OA and OB are
If the line 2x+3y+1=0 and 3x-y-4=0 lie along diameters of a circle of circumference 10π, then the equation of the circle is
The intercept made by the circle x2+y2-2hx sin θ-2ky sinθ=h2 cos2θ on the x-axis is