test_arctan = ->
	run_test [

		"arctan(x)",
		"arctan(x)",

		"arctan(-x)",
		"-arctan(x)",

		"arctan(0)",
		"0",

		"arctan(tan(x))",
		"x",

		"arctan(1/sqrt(3))-pi/6",	# 30 degrees
		"0",

		"arctan(1)-pi/4",		# 45 degrees
		"0",

		"arctan(sqrt(3))-pi/3",		# 60 degrees
		"0",

		"arctan(a-b)",
		"arctan(a-b)",

		"arctan(b-a)",
		"-arctan(a-b)",

		"arctan(tan(x))",
		"x",
	]