Multiplying complex numbers

From Graphic maths
Level: A Level Maths

Multiplying two complex numbers is similar to multiplying brackets in an algebraic equation.

Example

Suppose we have two complex numbers:

To multiply them, we multiply out the brackets:

We can simplify this by combining the terms in :

We can further simplify the expression using the fact that :

General case

To multiply two complex numbers and :

See also