| 释义 |
trigonometry|trɪgəˈnɒmɪtrɪ|
[ad. mod.L. trigōnometria (B. Pitiscus 1595), f. Gr. τρίγωνο-ν triangle + -µετρία measurement. So Fr. trigonométrie (1629 in Hatz.-Darm.).]
That branch of mathematics which deals with the measurement of the sides and angles of triangles, particularly with certain functions of their angles or of angles in general (the sine, cosine, tangent, cotangent, secant, and cosecant), and hence with these functions as applied to abstract quantities; thus including the theory of triangles, of angles, and of (elementary) singly periodic functions.
Trigonometry comprises plane trigonometry, which treats of plane triangles and angles, and spherical trigonometry, which treats of spherical ones, i.e. those described on the surface of a sphere.
[1595B. Pitiscus (title) Trigonometria: sive De Solvtione Triangvlorvm Tractatus breuis & perspicuus.] 1614(title) Trigonometry: or The Doctrine of Triangles. First written in Latine, by B. Pitiscus.., and now Translated into English, by Ra. Handson. 1631R. Norwood (title) Trigonometrie. Or, The Doctrine of Triangles: Divided into Two Bookes: The first shewing the mensuration of Right lined Triangles: The second of Sphericall. 1738Gentl. Mag. Jan. 13/1 A few Calculations by Trigonometry. 1816Playfair Nat. Phil. II. 13 It often happens..that the stars must be observed when they are not on the meridian, and their positions..must then be derived from spherical trigonometry. 1854Kingsley Alexandria i. 31 For the purpose of working out this theory he [Hipparchus] required a science of trigonometry plane and spherical: and this he accordingly seems to have invented. |