The term “trigonometry” literally means “measurement of triangles”. It was first used by a German mathematician Warfolomey Pittisc in 1595. Trigonometry is a part of mathematics, which studies dependences between angles and sides of triangles and trigonometrical functions (sine, cosine, tangent, cotangent, secant, and cosecant). Actually all trigonometrical functions were known by the end of the XVI century. Though they were not functions, but length of some chords, tangents and secants in a circle of a certain radius.
First records of trigonometry were found on the territory of Ancient Babylon. Astronomers and astrologists of Babylon were able to find the position of the Moon in any period of time. At that time they counted angles in degrees, minutes and seconds.
The most important achievements belong to scientists of Ancient Greece. In the II century B. C. a Greek astronomer Gipparkh from Nikkei made a table of dependences between parts of triangles. Though his table didn’t survive till the present time it is mentioned in “Almagest” written by a Greek astronomer and mathematician Claudius Ptolemy.
The terms “sine” and “cosine” came to us from India. Half of a chord in India was called “arkhadgiva”, which later was cut to “dgiva”. The Muslim astronomers got their knowledge from Indian scientists and “dgiva” was translated as “dgibe”. Finally, in the XII century “dgibe” was translated into Latin as “sinus”, which was cut top sine in the middle of the XVII century. By the end of the X century scientists of the Muslim world could operate with sine, cosine and four other trigonometrical functions – tangent, cotangent, secant and cosecant. Several theorems were developed and proved (theorem of sines and theorem of cosines) and a circle of an instance radius has been used from that time.
From the end of the XV century trigonometry changed its path from finding out new material to collecting it from all parts of the World. Such scientists as Isaac Newton, François Viet and Leonard Eiler put together the last parts of a puzzle called “Trigonometry”.
In different ages trigonometry was used in different spheres of human life. It helped us to make one of the 7 wonders of the world. In the Middle Ages almost all houses were made of wood. And special measuring instruments were made. One of them was a small mirror with degrees from 5 to 90 written on it. Several centuries later trains were invented. At that time – the end of the 19th century - trains seemed to be very dangerous for people, so special embankments were made. They were 9.8 m wide and the height of every embankment was 5.8m. Using the theorem of sines we can find out that its basement was 28.4m wide. In the middle of the 20th century multi-stored buildings appeared in Tokyo, New York, San Francisco and London. There were hundreds of stairs in them and people began to calculate how to make it easier to get to the top of the building. Using the theorem of sines we can find out that BC is equal to 21cm. Such width and height make it easier for us to get to the top floors.