The sine curve arch

In the investigation of the behaviour of arches the forms most often considered are the parabola and the circle, whilst from a practical aspect the parabola is the most
usual form. The elementary theory of the parabolic arch is not difficult but in more advanced analysis it may be convenient to consider the arch as a sine curve. The brief analysis outlined below compares the behaviour of a suitably chosen sine curve with that of a given parabolic arch with regard to some of the more familiar properties of the latter.

H. Waters