Question Number 87535 by mathmax by abdo last updated on 04/Apr/20
$${let}\:{U}_{{n}} =\left\{{z}\in{C}\:/{z}^{{n}} =\mathrm{1}\right\} \\ $$$${calculate}\:\sum_{{k}=\mathrm{0}\:{and}\:{z}\in{U}_{{n}} } ^{{p}−\mathrm{1}} \:{z}^{{k}} \\ $$
let-U-n-z-C-z-n-1-calculate-k-0-and-z-U-n-p-1-z-k-