For the parabola y2=16x, the ratio of the length of the sub-tangent to the abscissa at any point on the curve is
For the parabola y2=4 a x, the ratio of the sub-tangent to the abcissa is
The sub-tangent at any point of the curve xm yn=am+1 varies as
Length of the sub-tangent at any point P(x, y) on the parabola y2=4ax equals _____ the abscissa of the point P