6P-s-Tf2  7th point Tangent

Given 6 reference points P1, …, P6 and a random point P.
6P-s-Tf2(P) is the tangent at P to the unique circular cubic (see 7P-s-Cu1) defined by the seven points P, P1, …, P6.

Construction of a tangent at a circular cubic

See picture with description from Ref-63, p.212/213 in the French language from Roger Cuppens.

6P s Tf2 7th point Tangent