A. x2+y2+x-y-1=0
B. 6(x2+y2)+x-y-1=0
C. x2+y2+6(x-y)-1=0
D. 6x2+6y2+6x-6y-1=0
If the circles x2+y2=3a2 , x2+y2-6x-8y+9=0 touch externally then a=
The equation to the circles whose radius is 3 and which touches internally the circle x2+y2-4x+6y-12=0 at he point (-1, 1) is
The equation of the chord of contact of the point (4, 2) with respect to the circle x2+y2-5x+4y-3=0 is
The two circles x2+y2=a2, x2+y2=c2(c>0) touch each other if
The area of the quadrilateral formed by the tangents from the point (4,5) to the circle x2+y2-4x-2y-11=0 with a pair of radii joining the points of contact of these tangents is
The equation of the normal to the curve (x/a)2/3+(y/b)2/3=1 at (a cos3θ, b sin3θ ) is
The distance between the limiting points of the coaxial system x2 + y2 – 4x – 2y – 4 + 2λ(3x + 4y + 10)=0
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