""Elements of Analytic Trigonometry: Plane and Spherical"" is a mathematical textbook written by Ferdinand Rudolph Hassler and originally published in 1826. The book covers the principles and applications of analytic trigonometry, with a focus on both plane and spherical trigonometry. The author presents a comprehensive treatment of the subject, including discussions on the fundamental concepts of trigonometry, such as angles, functions, and identities,...