I've put this sum in the calculator: (2+√(2^2-20))/2, and i don;t understand what the answer (1.0000000000000940506249223285595+2.000000000000188101249844657119i) means.
Look here
https://www.khanacademy.org/math/precalculus/imaginary_complex_precalc/complex_num_precalc/v/complex-number-intro
