reserve p1, p2 for Point of TOP-REAL 2,
  C for Simple_closed_curve,
  P for Subset of TOP-REAL 2;

theorem Th5:
  for z being Complex, r being Real holds Rotate(z,-r) =
  Rotate(z,2*PI-r)
proof
  let z be Complex, r be Real;
  thus Rotate(z,-r) = |.z.|*cos (2*PI*1+(-r+Arg z))+ |.z.|*sin (-r+Arg z) *<i>
  by COMPLEX2:9
    .= Rotate(z,2*PI-r) by COMPLEX2:8;
end;
