Systematic study of trigonometric functions began in Hellenistic mathematics, reaching India as part of Hellenistic astronomy. During the Middle Ages, the study of trigonometry continued in Islamic mathematics, hence it was adopted as a separate subject history of trigonometry pdf the Latin West beginning in the Renaissance with Regiomontanus. The term “trigonometry” was derived from Greek τρίγωνον trigōnon, “triangle” and μέτρον metron, “measure”.
Our modern word “sine” is derived from the Latin word sinus, which means “bay”, “bosom” or “fold”, translating Arabic jayb. The Arabic term is in origin a corruption of Sanskrit jīvā, or “chord”. Sanskrit jīvā in learned usage was a synonym of jyā “chord”, originally the term for “bow-string”. Sanskrit jīvā was rendered into Arabic as jiba.
Particularly Fibonacci’s sinus rectus arcus proved influential in establishing the term sinus. The words “minute” and “second” are derived from the Latin phrases partes minutae primae and partes minutae secundae. These roughly translate to “first small parts” and “second small parts”. The ancient Egyptians and Babylonians had known of theorems on the ratios of the sides of similar triangles for many centuries.