The condition that the pair of tangents drawn from origin to the circle `x^2 +y^2 + 2gx+ 2fy+c=0` may be at right angle is

The condition that the pair of tangents drawn from the origin to the circle x^(2)+y^(2)+2gx+2fy+c=0 may be at right angles is

The condition that the pair of tangents drawn from origin to circle x^(2)+y^(2)+2gx+2fy+c=0 may be at right angles is

The condition that the pair of tangents drawn from origin to circle x^(2)+y^(2)+2gx+2fy+c=0 may be at right angles is

The squared length of the intercept made by the line x=h on the pair of tangents drawn from the origin to the circle x^2+y^2+2gx+2fy+c=0 is

The equation of the tangents drawn from the origin to the circle x^(2)+y^(2)-2gx-2fy+f^(2)=0 is

The tangents drawn from the origin to the circle : x^2+y^2-2gx-2fy+f^2=0 are perpendicular if:

A pair of tangents are drawn from the origin to the circle x^(2)+y^(2)+20(x+y)+20=0, The equation of pair of tangent is

Find the pair of tangents from the origin to the circle x^(2) + y^(2) + 2gx + 2fy + c = 0 and hence deduce a condition for these tangents to be perpendicular.