What are Complex Numbers?
A complex number is a number that can be written in the form a+ib, where a and b are the real numbers and i is the imaginary unit, where i^2=-1. Complex numbers are the extension of one dimensional number line to the two dimensional complex plane. The complex plane is used to represent real and imaginary parts of the complex graphically. It can be seen as a point or position vector in two dimensional Cartesian coordinate planes, which is also known as Argand diagram, named after French mathematician Jean-Robert Argand. Complex numbers are widely used in many other branches such as physics, chemistry, biology, economics, engineering and statistics with extensive practical use.