This is called the trapezoidal or chordal area, and will be denoted by C1.
The - - 4X + g tangential area may be expressed in terms of chordal areas.
If we write CI for the chordal area obtained by taking ordinates at intervals Zh, then T i =2CI-C I.
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.
2um) Now, if p is any factor of m, there is a series of equidistant ordinates uo, up, 142p, um - p, um; and the chordal area as determined by these ordinates is ph (2uo + up + u2p +.
The following are some examples of formulae of this kind, in terms of chordal areas.
The general method of constructing the formulae of § 7 0 for chordal areas is that, if p, q, r, ...
The following are the results (for the formulae involving chordal areas), given in terms of differential coefficients and of central differences.