ABSTRACT
In this book we first met complex numbers in Subsection 3.8.2 where they appeared in the solutions of certain algebraic equations. This is also the way in which complex numbers appeared in mathematics. Initially considered as impossible, with time the complex numbers have become indispensable in many fields of engineering and science. Using complex numbers it is easier to understand and solve problems that involve vibrations, alternating current, or control. And, as Penrose (2004) writes, understanding complex numbers is essential for understanding modern mathematics.
