Elusive Zeros under Newton’s Method


Though well-known for its simplicity and efficiency, Newton’s method applied to a complex polynomial can fail quite miserably, even on a relatively large open set of initial guesses. In this work, we present some analytic and numerical results for Newton’s method applied to the complex quartic family where is a parameter. The symmetric location of the roots of allows for some easy reductions. In particular, when λ is either real or purely imaginary, standard techniques from real dynamical systems theory can be employed for rigorous analysis. Classifying those λ-values where Newton’s method fails on an open set leads to complex and aesthetically intriguing geometry in the λ-parameter plane, complete with fractal-like figures such as Mandelbrot-like sets, tricorns and swallows.

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O’Brien, T. and Roberts, G. (2014) Elusive Zeros under Newton’s Method. Applied Mathematics, 5, 2393-2407. doi: 10.4236/am.2014.515231.

Conflicts of Interest

The authors declare no conflicts of interest.


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