A handy tool for computing poles and zeros and plotting the pole -zero locations , given the numerator and denominator polynomial coefficients of a transfer function.
The frequency response, magnitude as well as phase are also plotted.
the format for entering the polynomial coefficients is: A(1)+A(2)z^-1+A(3)z^-2+...+A(n-1)z^-n
Caution: Since the app uses Bairstow Alogrithm for computing the roots of polynomial, the convergence cannot be guaranteed for very high order polynomials.