reserve a,b for Complex;
reserve z for Complex;
reserve n0 for non zero Nat;

theorem Th8:
  for r being Real st r >= 0 holds n0-root r = n0-real-root r
proof
  let r be Real;
  reconsider r9=r as Real;
  assume
A1: r >= 0;
  then Arg r9 = 0 by COMPTRIG:35;
  hence thesis by A1,COMPLEX1:43,SIN_COS:31;
end;
