Subtracting Imaginary Numbers

Subtracting two imaginary numbers involves simply subtracting their imaginary coefficients: $$ (0,a) - (0,b) = (0,a-b) $$ Expressed in algebraic form, where (0,b) = bi, the subtraction looks like this: $$ a i - b i = (a-b)i $$

Example

Let's consider two imaginary numbers:

$$ (0,5) = 5i $$ $$ (0,3) = 3i $$

The difference between these two numbers is (0,2):

$$ (0,5) - (0,3) = (0,5-3) = (0,2) $$

When written in algebraic form, the subtraction yields the same result:

$$ 5i - 3i = (5-3)i = 2i $$

Note: Both forms represent the same imaginary number: 2i = (0,2). Since the imaginary unit is a constant (i = (0,1)), the imaginary number 2i can be expressed in algebraic form by multiplying the real number 2 by the imaginary unit (0,1): $$ 2i = 2 \cdot (0,1) = (2 \cdot 0, 2 \cdot 1) = (0,2) $$

And so forth.

 
 

Please feel free to point out any errors or typos, or share suggestions to improve these notes. English isn't my first language, so if you notice any mistakes, let me know, and I'll be sure to fix them.

FacebookTwitterLinkedinLinkedin
knowledge base

Complex Numbers