function dydt = gear_deriv ( t, y )

%*****************************************************************************80
%
%% gear_deriv() evaluates the right hand side of gear_ode().
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    04 June 2026
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real T, Y(2): the time and solution value.
%
%  Output:
%
%    real DYDT(2): the derivative value.
%
  u = y(1);
  v = y(2);
  dydt = [ 998.0 * u + 1998 * v; ...
         - 999.0 * u - 1999 * v ];

  return
end

