Jyā, koti-jyā and utkrama-jyā

Jyā, koṭi-jyā and utkrama-jyā are three trigonometric functions introduced by Indian mathematicians and astronomers.

Jyā and koti-jyā are closely related to the modern trigonometric functions of sine and cosine.

In fact, the origins of the modern terms of "sine" and "cosine" have been traced back to the Sanskrit words jyā and koti-jyā.

The Sanskrit word koṭi has the meaning of "point, cusp", and specifically "the curved end of a bow".

[1] According to one convention, the functions jyā and koti-jyā are respectively denoted by "Rsin" and "Rcos" treated as single words.

[3] The origins of the modern term sine have been traced to the Sanskrit word jyā,[4][5] or more specifically to its synonym jīvá.

However, in early medieval texts, the cosine is called the complementi sinus "sine of the complement", suggesting the similarity to kojyā is coincidental.