unit_test_equals("sin[0] == 0", ...
		 0, ...
		 divided_difference(@sin, 0));

unit_test_equals("sin[0, pi] == 0", ...
		 0, ...
		 divided_difference(@sin, [0,pi]));

unit_test_equals("sin[0, pi, 2*pi] == 0", ...
		 0, ...
		 divided_difference(@sin, [0,pi,2*pi]));
