Question

The distance between the chords of contact of tangents to the circle `x^2+y^2+2gx +2fy+c=0` from the origin & the point (g,f) is

Answer 1

`AB=x x_1+yy_1+2g(x+x_!)+f(y+y_1)+c`
`AB=gx+fy+c=0`
`2gx+2fy+2c=0`
`CD=gx+fy+gx+g^2+fy+f^2+c=0`
`=2gx+2fy+g^2+f^2+c=0`
`d=|(g^2+f^2+c-2c)/(2sqrt(g^2+f^2))|`
`=(g^2+f^2-c)/(2sqrt(g^2+f^2)`
option 3 is correct.