A. -4
B. 0
C. -8
D. 4
The equation of the circle passing through (-7, 1) and having centre at (-4, -3) is
The system of circles orthogonal to x2+y2+2x+4y+7=0 is a member, then the equation of the orthogonal system is
The circle described on the line joining the points (0, 1), (a, b) as diameter cuts the x-axis in points whose abscissa are roots of the equation
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