A new tabular form for determining root distribution of a complex polynomial with respect to the imaginary axis

The original Routh table dealing with real polynomials is further investigated for complex polynomials. A tabular form for determining root distribution of a complex polynomial with respect to the imaginary axis is developed, and modified procedures for directly treating singularities in the array are proposed. Also, procedures are developed for determining the respective orders of simple and/or repeated roots lying on the imaginary axis. Conditional stability and instability can be distinguished from each other by the criteria developed here