TITLE:
Enclosing Ellipses by Folding Disks
AUTHORS:
Peter Paul Klein
KEYWORDS:
Straight Line, Perpendicular Bisector, Linear System, Determinant, Point of Intersection, Gardner Ellipse, Bidirectional Folding
JOURNAL NAME:
Applied Mathematics,
Vol.13 No.2,
February
21,
2022
ABSTRACT: Ellipses can be constructed by folding disks. These folds are forming an envelope of tangents to the ellipse. In the paper of Gorkin and Shaffer, it was shown that the ellipse constructed by folding can be circumscribed by an arbitrary triangle of tangents, the vertices of which are lying on the circumference of the disk. They offered two non-elementary methods of proof, one using Poncelet’s Theorem, the other employing Blaschke products. In this paper, it is the intention to present an elementary proof by means of analytic geometry.