1. Vector approach to spherical trigonometry.

2. In the 13th century, Nasir al-Din Tusi (Nasireddin) made advances in spherical trigonometry.

3. Students may be confronted with difficulties in the application of complicated formulae of Spherical Trigonometry.

4. The mathematical models of the dynamic target and the tested apparatus are constructed with spherical trigonometry spherics.

5. The forward and inverse position kinematics solutions of the mechanism and corresponding numerical examples are given based on spherical trigonometry.

6. An early form of analogue computer(Sentencedict.com ), the astrolabe was primarily designed to solve problems of spherical trigonometry to shorten astronomical calculations.

7. Important in navigation, it is a special case of a more general formula in spherical trigonometry, the law of haversines, that relates the sides and angles of spherical triangles.

8. • Almagest Books 1 and 2 • the celestial sphere • numbers and angles (sexagesimal base-60) • obliquity and latitude and the related instruments • plane geometry and trigonometry, the chord tables • spherical trigonometry, circles on the celestial sphere