Let PQ be a focal chord of the parabola y2 = 4px. LetM be the midpoint of PQ. A perpendicular is drawn from M to thex-axis, meeting the x-axis at S. Also from M, a line segment isdrawn that is perpendicular to PQ and that meets the x-axis at T.Show that the length of ST is one-half the focal width of theparabola.
