A new general Routh-like algorithm to determine the number of RHP roots of a real or complex polynomial
S. D. Agashe · IEEE Transactions on Automatic Control · 1985
A new Routh-like algorithm for determining the number of right-half plane (RHP) roots of a polynomial with real or complex coefficients is given. It includes the Routh algorithm for real polynomials as a special case. Moreover, the algorithm also applies directly to the singular case wherein the leading coefficient of a row, but not the entire row, vanishes, needing far fewer computations than the heuristicepsilon- method about which there was a vigorous discussion in these TRANSACTIONS a few years ago, and further not requiring investigation of an auxiliary polynomial. The algorithm is illustrated by a few examples. The proof of the algorithm is based on the Principle of the Argument, and thus also constitutes a simple proof of the Routh algorithm in the regular case.