# Arithmetic Course/Types of Number/Imaginary Number

## Imaginary Number

Imaginary Number is defined as

${\displaystyle i={\sqrt {-1}}}$

## Mathematic Operations

i + 0 = i
i + i = 2i
i + (-i) = 0

i - 0 = i
i - i = 0
i - (-i) = 2i

### Multiplication

i x 0 = 0
i x i = i2 = -1
i x (-i) = -i2 = 1

i / 0 = ∞
i / i = 1
i x (-i) = -1