Method of Successive Polynomial Substitutions for Computing Roots of Polynomials

Abstract

A recursive technique, termed method of successive polynomial substitutions for computing all the real and complex roots of a polynomial of any given degree, is introduced. The method proceeds by reducing the degree of polynomial by one at each stage of successive polynomial substitutions; extracts a root, and continues until reaching a second-degree polynomial whose roots are obtained analytically. Coefficients of the polynomial may be real or complex; no initial guess is needed and the results are highly accurate. Sample computations for polynomials of various degrees and the code used in computations are given.