Annular bounds for the zeros of a polynomial from companion matrix

Pintu Bhunia, Kallol Paul

Let $p(z)=z^n+a_{n-1}{z}^{n-1}+a_{n-2}{z}^{n-2}+\dots +a_{1}z+a_0$ be a complex polynomial with $a_0\ne 0$ and $n\ge 3$. Several new upper bounds for the moduli of the zeros of $p$ are…