>>> from integrals import integra

>>> round(integra(1, 2, 8), 3)
9.621
>>> round(integra(1, 2, 40), 3)
9.623
>>> round(integra(1, 2, 4), 3)
9.615
>>> round(integra(1, 2, 2), 3)
9.591
>>> round(integra(5, 10, 8), 1)
604.1
>>> round(integra(5, 10, 40), 1)
604.4
>>> round(integra(5, 10, 10), 1)
604.3
>>> round(integra(5, 10, 2), 1)
599.6