Properties of Polynomial Roots - Continuous Dependence of Coefficients

Continuous Dependence of Coefficients

The n roots of a polynomial of degree n depend continuously on the coefficients.

This result implies that the eigenvalues of a matrix depend continuously on the matrix. A proof can be found in a book of Tyrtyshnikov (see section References below).

The problem of approximating the roots given the coefficients is ill-conditioned. See, for example, Wilkinson's polynomial.

Read more about this topic:  Properties Of Polynomial Roots

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