As the earth is also a sphere, trigonometry is used in geography and in navigation. Columbus carried a copy of Regiomontanus' Ephemerides Astronomicae on his trips to the new world and used it to his advantage. Although trigonometry was first applied to spheres, it has had greater application to planes. Surveyors have used trigonometry for centuries. Engineers, both military engineers and otherwise, have used trigonometry nearly as long.
Physics lays heavy demands on trigonometry.
Optics and statics are two early fields of physics that use trigonometry, but all branches of physics use trigonometry since trigonometry aids in understanding space. Related fields such as physical chemistry naturally use trig. Of course, trigonometry is used throughout mathematics, and, since mathematics is applied throughout the natural and social sciences, trigonometry has many applications. Calculus, linear algebra, and statistics, in particular, use trigonometry and have many applications in the all the sciences. Table of contents .