A. r2-a2+b2

B. 2(r2-a2+b2)

C. √r2-a2+b2

D. 2√r2-a2+b2

The tangents drawn from the origin to the circle x^{2}+y^{2}-2rx-2hy+h^{2}=0 are perpendicular if

If x^{2}+y^{2}-2x+3y+k=0 and x^{2}+y^{2}+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 x^{2}+y^{2}=2ax and x^{2}+y^{2}=2by and having its centre on the x/a-y/b=2 is

If O is the origin and OP, OQ are the tangents to the circles x^{2}+y^{2}+2gx+2fy+c=0 then the circumcentre of the ΔOPQ is

If a circle passes through the point (a, b) and cuts the circle x^{2}+y^{2}=k^{2} orthogonally, the equation of the locus of its centre is