function z = polar_exact ( t )

%*****************************************************************************80
%
%% polar_exact() evaluates the exact solution of polar_ode().
%
%  Discussion:
%
%    The variable Z(t) is complex, and has the formula:
%
%    theta = t;
%    r = 1 - sin(theta) * cos(3*theta)
%    z = r * exp ( i * theta )
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    10 March 2021
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real T(:): the evaluation times.
%
%  Output:
%
%    complex Z(:): the exact solution values.
%
  r = 1.0 - sin ( t ) .* cos ( 3.0 * t );
  z = r .* exp ( i * t );

  return
end

