A. x2+ax+b=0
B. x2-ax+b=0
C. x2+ax-b=0
D. x2-ax-b=0
If the length of the tangent from (h, k) to the circle x2+y2=16 is twice the length of the tangent from the same point to the circle x2+y2+2x+2y=0, then
The equation of the circle concentric with circlex2+y2-6x+12y+15=0 and of double its area is
The equation of the circle passing through the points of intersection of the circlesx2+y2=5, x2+y2+12x+8y-33=0 and touching x-axis is
If 4y=x+7 is diameter of the circumscribing circle of the rectangle ABCD and A(-3, 4), B(5, 4), then the area of the rectangle is
The polar of the point(2t, t-4) w.r.t the circle x2+y2-4x-6y+1=0 passes through the point
The locus of midpoints of chords of the circle x2+y2=2r2 subtending a right angle at the centre of the circle is
The centres of the circles are (a, c) and (b, c) and their radical axis is the y-axis. The radius of one of the circle is r. The radius of the other circle is
The tangents drawn from the origin to the circle x2+y2-2rx-2hy+h2=0 are perpendicular if
If x2+y2-2x+3y+k=0 and x2+y2+8x-6y-7=0 cut each orthogonally, the value of k must be
The equation of the circle passing through the intersection of the circles x2+y2=2ax and x2+y2=2by and having its centre on the x/a-y/b=2 is