I am learning how to find cube roots of a complex number and I wanted to see if I am doing this right. could someone let me know?

find the cube roots of -8i:

$\displaystyle

8(cos (3\pi/2)+ i sin(3\pi/2))

$

$\displaystyle

(8)^1/3[cos((3\pi/2)+2\pi(k)/3) + i sin((3\pi/2)+2\pi(k)/3)]

$

$\displaystyle

k= 0, 1, 2

$

$\displaystyle

2(cos(\pi/2) + i sin(\pi/2))

$

Is this good so far? I just done the first one to see if I done it right.