function jac = p01_jac ( option, nvar, x )

%*****************************************************************************80
%
%% P01_JAC evaluates the jacobian for problem 1.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    06 September 2008
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, integer OPTION, the option index.
%
%    Input, integer NVAR, the number of variables.
%
%    Input, real X(NVAR), the argument of the jacobian.
%
%    Output, real JAC(NVAR-1,NVAR), the jacobian matrix evaluated
%    at X.  The NVAR-th row is not set by this routine.
%
  jac = zeros ( nvar, nvar );

  jac(1,1) = 1.0;
  jac(2,1) = 1.0;

  jac(1,2) = ( - 3.0 * x(2) + 10.0 ) * x(2) -  2.0;
  jac(2,2) = (   3.0 * x(2) +  2.0 ) * x(2) - 14.0;
%
%  Get the starting point
%
  y = p01_start ( option, nvar );
%
%  Get the function value at the starting point
%
  gy = p01_gx ( y );

  jac(1,3) = gy(1);
  jac(2,3) = gy(2);

  return
end