Argand diagrams

From Graphic maths
Level: A Level Maths

An Argand diagram is a way of representing complex numbers on a diagram.

Complex numbers in 2 dimensions

A real number can be represented as a point on a number line.

Since a complex number has two components (the real part and the imaginary part), it cannot be represented as a point on a line, but instead it can be represented as a point on a plane.

Argand diagram

In an Argand diagram, we represent a complex number:

as a point on a graph using Cartesian coordinates.

The coordinate represents the real value, so the x-axis is called the real axis. The coordinate represents the imaginary value, so the y-axis is called the imaginary axis.

Argand.png

In this diagram:

  • Point A, with an value of 4 and a value of 3, represents the complex number .
  • Point B, with an value of -2 and a value of 3, represents the complex number .
  • Point C, with an value of -3 and a value of -1, represents the complex number .

See also