Prove that the semi-latus rectum of the parabola `y^2 = 4ax` is the harmonic mean between the segments of any focal chord of the parabola.

The Harmonic mean of the segments of a focal chord of the parabola y^(22)=4ax is

The harmonic mean of the segments of a focal chord of the parabola y^(2)=16ax, is

The harmonic mean of the segments of a focal chord of the parabola y^(2)=16ax, is

Length of the semi-latus -rectum of parabola : x^(2) = -16y is :

If l denotes the semi-latus rectum of the parabola y^2= 4ax and SP and SQ denote the segments of any focal chord PQ, S being the focus, then SP, l and SQ are in the relation :

Find the length of the Latus rectum of the parabola y^(2)=4ax .

Find the equations of the normals at the ends of the latus- rectum of the parabola y^2= 4ax. Also prove that they are at right angles on the axis of the parabola.