SOLUTION: Find the 3 cube roots of -i in POLAR FORM: rcis(theta).

In polar form

    -i = .     (1)


According to the DeMoivre's theorem, the three cube roots of -i are these three complex numbers in polar form


    a)   = 


    b)   =  =  = 


    c)   =  =  = 


The argument of the first root is    of the argument of the right side equation (1).


The arguments of the second and third root have consecutive increments of   from the argument of the first root.