# History of Trigonometry

The **history of trigonometry** dates back to the early ages of Egypt and Babylon . Angles were then measured in degrees. History of trigonometry was then advanced by the Greek astronomer Hipparchus who compiled a trigonometry table that measured the length of the chord subtending the various angles in a circle of a fixed radius r.This was done in increasing degrees of 71.

In the 5 th century, Ptolemy took this further by creating the table of chords with increasing 1 degree. This was known as Menelaus's theorem which formed the foundation of trigonometry studies for the next 3 centuries. Around the same period,

Indian mathematicians created the trigonometry system based on the sine function instead of the chords. Note that this was not seen to be ratio but rather the opposite of the angle in a right angle of fixed hypotenuse. The history of trigonometry also included Muslim astronomers who compiled both the studies of the Greeks and Indians .

In the 13 th century , the Germans fathered modern trigonometry by defining trigonometry functions as ratios rather than lengths of lines. After the discovery of logarithms by the Swedish astronomer, the history of trigonometry took another bold step with Issac Newton. He founded differential and integral calculus. Euler used complex numbers to explain trigonometry functions and this is seen in the formation of the Euler's formula.

The history of trigonometry came about mainly due to the purposes of time keeping and astronomy.