[L_Von_Mises]

There is no square root of any negative number.

The square root of -1 is i, and the square root of any negative number is simply i* the square root of the absolute value of the number that you are taking the square root of.

[supercat]

The square root of -1 is i, and the square root of any negative number is simply i* the square root of the absolute value of the number that you are taking the square root of.

Calling the square root of -1, i is just convention, but the square root of i can be derived mathematically as +/-(i+1)*sqrt(2)/2. I'm sure you knew that, but others here may not.