De sinibus, chordis et arcubus

De sinibus, chordis et arcubus (On Sines, Chords, and Arcs) is a 1342 work by the French Jewish mathematician, philosopher, astronomer, and Talmudic scholar Levi ben Gershom. In this treatise, Levi ben Gershom presented an original derivation of the sine theorem for plane triangles and created sine tables calculated to five decimal places. Trigonometry, which derives its name from Greek words meaning "triangle" and "to measure," historically focused on calculating missing parts of triangles. The sine theorem, a fundamental concept in trigonometry, relates the lengths of the sides of a triangle to the sines of its opposite angles. The term "arcsine" refers to the inverse function of the sine.123