Dividing complex numbers has a trick to it.

first thing to realize is that it's always easier to multiply than to divide. Doing so simplyfies your problem.

for example, if you have a simple division as such:

$ \frac{5}{\sqrt{2}} $

it would be easier to solve if you multiply by:

$ \frac{5}{\sqrt{2}} * \frac{\sqrt{2}}{\sqrt{2}} = \frac{5}{2} * \sqrt{2} $

With complex numbers, say you want to divide $ \frac{(2 + i)}{3 - i} $

it would be suitable to multiply top and bottom by the complex conjugate of the denominator.

$ \frac{(2 + i)}{3 - i} * \frac{(3 + i)}{3 + i} $

this would give a $ 10 $ in the denominator.

simplifying the expression into:

$ \frac{5 + 5i}{10} $ or $ \frac{1 + 1i}{2} $

which is the solution!

Alumni Liaison

Basic linear algebra uncovers and clarifies very important geometry and algebra.

Dr. Paul Garrett