Identifying Break Points In Root Locus Using Bolzano Theorem

In linear control systems Evans rules are used to manually sketch the root locus. One of these rules concerns identifying break-in or breakaway points. Multitude of analytical methods can provide such break points. However even to verify the existence of break points each method requires solving an equation. In this paper using Bolzano theorem we propose a method of checking the existence of break points in a specific interval without need to solve any equation.