Root of a negative number
The root of a negative number must be reduced to an arithmetic root in order to calculate it, with
Explanation
Negative numbers can be converted with the imaginary unit. You then eliminate the minus sign. In a multiplication you get
The calculation
is wrong. So is the next calculation
although the result is correct, but the operations are incorrect. The property
is valid only for mathematical roots. Algebraic roots must first be reduced to arithmetic roots.