Argand Diagrams

Since the complex numbers can be written in the form x+iy, where x and y are real numbers, they may be represented by points in a Cartesian plane.

Therefore the points P and Q in the adjacent figure could be taken to represent the complex numbers  3+i and -1+2i respectively. Such a diagram representing complex numbers in this way is called an ARGAND DIAGRAM.

In this representation, the x co-ordinate represents the real part and the y co-ordinate represents the imaginary part. For this reason, the x-axis is often referred to as REAL axis and the y-axis is referred to as the IMAGINARY axis.