Hjem
Matematisk institutt

Captain Lill's method: "solving" every polynomial equation by geometry

Fellesseminar

Hovedinnhold

Speaker: Professor Dr. Rainer Kaenders, Department of Mathematics, University of Bonn, Germany

Captain Lill's method: "solving" every polynomial equation by geometry

The Austrian engineer Eduard Lill invented in 1867 a visual method of finding the real roots of real polynomials of any degree. Lill's method involves expressing the coefficients of a polynomial as magnitudes of a sequence of segments at right angles to each other. Finding the real roots is then translated into solving a purely geometrical problem in this construction. In the talk we explain this method in detail and explore some of its features, that are related to Horner's scheme, to ancient methods for pulling roots and to paper folding.