Notice that -32i = . Therefore, due to DeMoivre formulas, the 5-th degree roots of -32i are (1) 2cis(54°); ( notice that 54° = ); (2) = = 2cis(54° + 72°) = 2cis(126°); ( Notice that 72° = ) (3) = 2cis(54° + 2*72°) = 2cis(198°); (4) = 2cis(54° + 3*72°) = 2cis(270°); (5) = 2cis(54° + 4*72°) = 2cis(342°).