@article {MATHEDUC.06331444,
author = {Northshield, Sam},
title = {Geometry of cubic polynomials.},
year = {2013},
journal = {Mathematics Magazine},
volume = {86},
number = {2},
issn = {0025-570X},
pages = {136-143},
publisher = {Mathematical Association of America (MAA), Washington, DC},
doi = {10.4169/math.mag.86.2.136},
abstract = {Summary: Imagine a sphere with its equator inscribed in an equilateral triangle. This Saturn-like figure will help us understand from where Cardano's formula for finding the roots of a cubic polynomial $p(z)$ comes. It will also help us find a new proof of Marden's theorem, the surprising result that the roots of the derivative $p^{\prime}(z)$ are the foci of the ellipse inscribed in and tangent to the midpoints of the triangle determined by the roots of the polynomial.},
msc2010 = {G75xx},
identifier = {2014e.00582},
}