The property of a conic: “if the projections of K, any point on a tangent, on the directrix and the focal radius of the point of contact be I and U respectively, SU = e. KI,” is known as Adams's Property. The statement of the above property in terms of the polar coordinates of K is the equation of the tangent. Hence, if the eccentric angle of the point of contact is a

or = cos (θ — α) + e cos θ is the equation of the tangent.