Most trigonometry students look at triangles on a flat surface. However, people from ancient astronomers to modern navigators calculated the arc lengths and angles of triangles on a sphere. They used ...

Most trigonometry students look at triangles on a flat surface. However, people from ancient astronomers to modern navigators calculated the arc lengths and angles of triangles on a sphere. They used ...

FOUR of the most important formulæ in spherical trigonometry were given by Gauss, without proof, in his “Theoria Motus Corporum Cœlestium” (1809), and were therefore called Gauss's theorems ...

After successfully executing a daring operation on the Normandy coast, the British now knew how the Germans had been ...