Drawing Tangent and Normal to any conic

When a tangent at any point on the curve (P) is produced to meet the directrix, the line joining the focus with this meeting point (FT) will be at right angle to the line joining the focus with the point of contact (PF).
The normal to the curve at any point is perpendicular to the tangent at that point.

 

  Figure 9. The method of drawing tangent and normal to any conic section at a particular point.