About the determination of the center and axis of a direct similarity in 3D

  1. Roanes Macías, Eugenio
Revista:
Boletín de la Sociedad Puig Adam de profesores de matemáticas

ISSN: 1135-0261

Any de publicació: 2019

Títol de l'exemplar: Profesor Joaquín Hernández Gómez

Número: 108

Pàgines: 57-72

Tipus: Article

Altres publicacions en: Boletín de la Sociedad Puig Adam de profesores de matemáticas

Resum

A 3D direct similarity defined by a tetrahedron and its image tetrahedron of proportional edges is considered. This similarity is a "dilative rotation", consisting of a rotation around an axis and a stretch with center in the rotation axis. Methods of synthetic geometry are used in this paper for determining such center and axis. Finally, methods of elementary analytic geometry with matrix calculus are used for solving concrete examples in a brief way.