The root of a negative number is an imaginary number. It is denoted by i which is represented as -1.
An imaginary number is a complex number that can be written as a real number multiplied by the imaginary unit i, which is defined by its property i2 = −1.
Example: Solve x2 = −1
Using Real Numbers there is no solution, but now we can solve it!
Take the square root of both sides:
x = ± √(−1)
x = ± i
Answer: x = −i or +i
(−i)2 = (−i)(−i) = +i2 = −1
(+i)2 = (+i)(+i) = +i2 = −1