Vermutlich meinst du:
(4 - 4 √(3) i )1/3 = (4 (1- √(3) i) )1/3
1 - √3 i skizzieren und Polarkoordinaten ablesen (Pythagoras anwenden)
r = √4 = 2
phi = arctan (-√3/1) = -60° = -pi/3
1 - √3 i = 2*e^{-ipi/3}
(4 - 4 √(3) i) )1/3 = (4 (1- √(3) i) )1/3 = (4*2*e^{-ipi/3} )1/3
= 2* e^{-ipi/9}
= 2*(cos (-pi/9) + i sin(-pi/9) )
= 2*cos (-pi/9) + i 2 sin(-pi/9)
= 1.879 - 0.684 i
Zweite Lösung
= 2* e^{i(2pi/3 - pi/9)}
= 2*(cos (2pi/3 - pi/9) + i sin(2pi/3 - pi/9) )
= 2*cos (2pi/3 - pi/9) + i 2 sin(2pi/3 - pi/9)
= -0.347 + 1.970 i
Dritte Lösung
= 2* e^{i(4pi/3 - pi/9) }
= 2*(cos (4pi/3 - pi/9) + i sin(4pi/3 - pi/9) )
= 2*cos (4pi/3 - pi/9) + i 2 sin(4pi/3 - pi/9)
= -1.532 – 1.286 i
Kontrolle https://www.wolframalpha.com/input/?i=%284+-+4+√%283%29i+%29%5E%281%2F3%29