function value = pendulum_exact ( t, y0 )

%*****************************************************************************80
%
%% pendulum_exact returns the exact solution of the pendulum test problem.
%
  u0 = y0(1);
  v0 = y0(2);

  u =   u0 * cos ( t ) + v0 * sin ( t );
  v = - u0 * sin ( t ) + v0 * cos ( t );

  value = [ u, v ];

  return
end

