- (geometry, mathematical analysis) The branch of mathematics that deals with the relationships between the sides and angles of (in particular) right-angled triangles, as represented by the trigonometric functions, and with calculations based on said relationships.
- 1892, Edward Albert Bowser, A Treatise on Plane and Spherical Trigonometry, D. C. Heath & Co., page 1,
- Trigonometry was originally the science which treated only of the sides and angles of plane and spherical triangles; but it has been recently extended so as to include the analytic treatment of all theorems involving the consideration of angular magnitudes.
- 2013, Paul Abbott, Hugh Neill, Trigonometry: A Complete Introduction, Hachette, unnumbered page,
- In fact, the earliest practical uses of trigonometry were in the fields of astronomy and hence navigation.
- 2016, Carl F. Lorenzo, Tom T. Hartley, The Fractional Trigonometry, Wiley, page 8,
- The properties of these new trigonometries and identities flowing from the definitions are then developed.
- The trigonometries derived from these generalizations will be jointly termed "The Fractional Trigonometry."
- (branch of mathematics): trig (informal, abbreviation)
branch of mathematics
- Trigonometric functions on Wikipedia.Wikipedia
- Trigonometric tables on Wikipedia.Wikipedia
- Pythagorean trigonometric identity on Wikipedia.Wikipedia
- List of trigonometric identities on Wikipedia.Wikipedia