ABSTRACT
Every new number system in the history of mathematics created cognitive problems which were often not resolved for centuries. Each system was encountered in the solution or completeness of a classical problem. Solutions to the quadratic and cubic polynomial equations were presented by Cardan in 1545, who apparently regarded the complex numbers as fictitious but used them formally. The following numerical method, attributed to Bernoulii, can be employed to find the dominant root of a polynomial. The method can be employed as a quick numerical method to check if a discrete time system is stable. If there are several roots of the same modulus, then the method is modified and shifts are employed. The transfer function of every continuous time-invariant linear system is meromorphic in the complex plane. Most texts base their exposition of the theory of a complex variable on Cauchy’s approach incorporating a slight weakening of the definition due to Goursat.
