(Updated on 2/11/2020)

The complex plane is similar to the Cartesian plane we learn in junior form. However, the complex plane is used to represent complex numbers. Here are some basic concept of complex plane.

Consider z=3+4i,

1. The horizontal axis is called the real axis, it represents the real part of the complex number. The vertical axis is called the imaginary axis, it represents the imaginary part of the complex number. (Example : 3+4i)

2. The modulus (absolute value) is defined by sqrt(3^2+4^2), which is 5.

3. The argument of z is defined by the angle of the radius Oz with the positive real axis. For example, the argument of z is arctan(4/3).

4. The complex conjugate of the complex number z =3+4i is given by 3− 4i.