On region containing all the zeros of a polynomial

In this paper we present a result providing an annulus containing all the zeros of a polynomial with complex coefficients. Our theorem includes as special cases several results known in this direction. Besides, we show that as corollaries this theorem can generate many more results of this type. Also, we develop MATLAB code to construct polynomials for which the bounds obtained by our results are better than obtainable from some of the known results.