trigonometrical, a.
(ˌtrɪgənəʊˈmɛtrɪkəl)
[f. trigonometry or mod.L. trigonometria + -ic + -al1; after geometrical, etc.]
Of, pertaining to, or performed by trigonometry.
trigonometrical functions, those functions of an angle, or of an abstract quantity, used in trigonometry, viz. the sine, tangent, secant, etc.: see trigonometry. trigonometrical point, trigonometrical station, a reference point on high ground, usu. marked by a small pyramidal structure, used in triangulation. trigonometrical survey, a survey of a country or region performed by triangulation and trigonometrical calculation.
| 1666 [implied in trigonometrically]. 1690 Leybourn Curs. Math. 552 To find the Altitude..by Trigonometrical Calculation. 1706 W. Jones Syn. Palmar. Matheseos 278 Any three..being given, the other three may be found by Trigonometrical Calculation. 1758 Murdoch in Phil. Trans. L. 543 A table of the trigonometrical analogies. 1801 Capt. W. Madge (title) Account of the Operations carried on for accomplishing a Trigonometrical Survey of England and Wales, 1797. 1807 Hutton Course Math. (1811) II. 3 A Trigonometrical Canon is a table showing the length of the sine, tangent, and secant, to every degree and minute of the quadrant, with respect to the radius, which is expressed by unity or 1. 1860 Tyndall Glac. i. xi. 69 A pyramid of stones used as a trigonometrical station by Professor Forbes. 1886 T. P. White Ordnance Survey of U.K. iv. 68 In very many cases the old trigonometrical points were again observed to or from. 1949 T. W. Birch Maps vi. 56 The trigonometrical points or stations determined by theodolite are accurately plotted on the plane-table sheet. |