def test_section_modulus_and_polar_second_moment_of_area():
a, b = symbols('a, b', positive=True)
x, y = symbols('x, y')
rectangle = Polygon((0, b), (0, 0), (a, 0), (a, b))
assert rectangle.section_modulus(Point(x, y)) == (a*b**3/12/(-b/2 + y), a**3*b/12/(-a/2 + x))
assert rectangle.polar_second_moment_of_area() == a**3*b/12 + a*b**3/12
convex = RegularPolygon((0, 0), 1, 6)
assert convex.section_modulus() == (5/S(8), 5*sqrt(3)/S(16))
assert convex.polar_second_moment_of_area() == 5*sqrt(3)/S(8)
concave = Polygon((0, 0), (1, 8), (3, 4), (4, 6), (7, 1))
assert concave.section_modulus() == (-6371/S(429), -9778/S(519))
assert concave.polar_second_moment_of_area() == -38669/S(252)
