Complex Numbers: Lecture 4

There are mainly two learning points in this lecture.

1. How to make use of the property of modulus and argument
2. the polar form of complex numbers.


In general, the property of argument is similar to the laws of logarithms. The properties are very important. Make sure that you are familiar with them and do not get confused between the properties of modulus and argument.

For the polar form of complex number, \[z=r(sin\theta+icos\theta)\], where r is the modulus (distance from z to the origin in argand diagram) and \[\theta\] is the argument (angle between the complex number and the positive x-axis in argand diagram)

Given the polar form, you can get the cartesian form easily by calculating \[sin\theta\] and \[cos\theta\].

Given the cartesian form, if you want to get the polar form, find the modulus and the argument first.

After this lecture, you can attempt tutorial 10b Q1, Q3, Q5, Q6, Q7 and Q13