Ich rechne dir mal die Aufgabe vor:
z = 3√(5-i4)
φ = arctan(-4/5) + 2π
z = 3√( √(41) * ei5,6084 )
z0 =1,8569 * ei1,8694 = 1,8569 * (cos(1,8694) + sin(1,8694)*i)
= -0,54 + 1,77*i
z1 = 1,8569 * ei*(1,8694 + 2/3*pi) = 1,8569 * ei*3,963 = -1,2649 -1,359*i
z2 = 1,8569 * ei*(1,8694 + 4/3*pi) = 1,8569 * ei*6,058 = +1,81 -0,41462*i