function y = brad(x)
% function y = brad(x)
%
% The Bring radical of a real vector,
% the real root to the quintic equation
%   z⁵ + z - x = 0
% with discriminant 3125x⁴ + 256 > 0
n = length(x);
y = zeros(n,1);
for j=1:n
  z = mroots([1 0 0 0 1 -x(j)]);
  [t,m] = min(abs(imag(z)));
  y(j) = z(m);
end