fprintf ( 1, '\n' );
fprintf ( 1, 'bill2_newton_system1:\n' );
fprintf ( 1, '  Use Newton''s method for a root of the bill2 function.\n' );

x = [ 1.0; 1.0 ];
xtol = 0.0000001;
ftol = 0.0000001;
itmax = 50;

[ x, it ] = newton_system1 ( @(x)bill2(x), @(x)bill2_fp(x), x, xtol, ftol, itmax );

fprintf ( 1, '\n' );
fprintf ( 1, '  Number of steps = %d\n', it );
fprintf ( 1, '  x = (%g, %g)\n', x );
fprintf ( 1, '  f(x) = (%g, %g)\n', bill2(x) );

