The following are some examples of formulae of this kind, in terms of chordal areas.
This is called the trapezoidal or chordal area, and will be denoted by C1.
The following are the results (for the formulae involving chordal areas), given in terms of differential coefficients and of central differences.
To illustrate the method, suppose that we use the chordal area C1, and that the trapezette is in fact parabolic. The difference between C 1 and the true area is made up of a series of areas bounded by chords and arcs; this difference becoming less as we subdivide the figure into a greater number of strips.
Some of the formulae obtained by the above methods can be expressed more simply in terms of chordal or tangential areas taken in various ways.