he ancient Egyptians and Babylonians had known of theorems on the ratios of the sides of similar triangles for many centuries. But pre-Hellenic societies lacked the concept of an angle measure and consequently, the sides of triangles were studied instead, a field that would be better called "trilaterometry".

Albuzjani, an Arab scholar, is born. Albuzjani furthered the field of trig by introducing a new trig function when he constructed his table of tangent ratios.

Hipparchus, a Greek astronomer and mathematician, is often fondly referred to as "the father of trigonometry." Using a very primative form of trigonometry using circles and chords, Hiparchus compiled the first know star catalog and developed a system of identifying places on the surface of the earth by their latitude and longitude. This system is still in use to some extent today.

Some 300 years after Hipparchus developed the basic of trig, Ptolemy expaned on his works greatly. Since most of Hipparchus' works had been lost, it was largely due to Ptolemy that the fundamental ideas of trigonometry were presented to the world. Ptolemy is also famous for incorrectly supporting the idea that our universe was earth-centered and that Asia extended much further west than it actually did.

Gerardo of Cremona works to translate the works of Ptolemy and Hipparchus from Arab into Latin

The field begins to take on a language of its own (turning from Latin to Greek) and in 1595 the first known instance of the work "trigonometry," (from the Greek: trigonon=triangle, metron=to measure). This replaced a previous Greek term "goniometry" that was previously used to describe teh study of angle measurement.

Albert Girard becomes the first mathematician to use the sine, cosine, and tangent abbreviations that are now so common (sin, cos, tan). Students still use these abreviations in math classrooms around the country.

Trigonometry once again causes a stir, when Joseph Fourier publishes his studies taht show how equations built from repeated sine and cosine waves can be used to construct a better understanding of the mechanics of light, heat, and sound. Our modern day Physics classrooms would not be the same without this discovery.

Johann Regiomontanus helps to fix many of the translation errors in Gerardo's work and creates his own modern exposition and study on trigonometry.

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