HISTORY OF TRIGONOMETRY; ITS ORIGIN AND DEVELOPMENT

Hello steemians NAMASTE. I want to give a historical note in TRIGONOMETRY(in MATHEMATICS).

The study of trigonometry was first started in India.The ancient Indian Mathematicians, Aryabhatta(476),Brahmaputra(598),Bhaskara I (600) and Bhaskara II (1114) got important results.





All this knowledge first went from India to middle-east and from there to Europe. The Greeks had also started the study of trigonometry but their approach was so clumsy that when the Indian became known, it was immediately adopted throughout the world.





In India,the predecessor of the modern trigonometric functions, known as the sine of an angle, and the introduction of the sine function represents the main contribution of the siddhantas(Sanskrit astronomical works) to the history of mathematics.



Bhaskara I (about 600) gave formula to find the values of sine functions for angles more than 90°. A sixteenth century Malayalam work Yuktibhasa (period) contains the proof for the expansion of sin(A+B). Exact expression for sines or cosines of 18°, 36°, 54°,72°, etc. are given by Bhaskara I.


The symbols sin^-1x , cos^-1x , etc. for arc sin x , arc cos x , etc. were suggested by the astronomer Sir John F.W. Herschel(1813). The names of Thales(about 600 B.C.) is associated with height and distance problems. Thales also calculated the distance of a ship at sea through the proportionality of sides of similar triangles.