Complex Numbers

Imaginary roots 

x^2 + 4 = 0

--> x ^ 2 = - 4 

--> x = √- 4

--> x = √4 * √- 1 

--> x = + 2 i or - 2 i where i = √ - 1 is called imaginary number which gave rise to an important branch of mathematics called Complex Numbers.....