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Q: "trigonometric table" ( Answered,   0 Comments )
Subject: "trigonometric table"
Category: Reference, Education and News > Teaching and Research
Asked by: mariahc17-ga
List Price: $2.50
Posted: 01 Jun 2003 11:00 PDT
Expires: 01 Jul 2003 11:00 PDT
Question ID: 211577
How was the trigonometric table created?
Subject: Re: "trigonometric table"
Answered By: aditya2k-ga on 01 Jun 2003 11:26 PDT
Hi Mariah,

Good day and thanks for your question.

There is an excellent webpage (
) which gives the development of trigonometry.

I'll quote the following from the article :

"In the 2nd century BC the astronomer Hipparchus compiled a
trigonometric table for solving triangles. Starting with 71 and going
up to 180 by steps of 71, the table gave for each angle the length
of the chord subtending that angle in a circle of a fixed radius r.
Such a table is equivalent to a sine table."

"Ptolemy provided a table of chords for steps of 1, from 0 to 180,
that is accurate to 1/3600 of a unit. He also explained his method for
constructing his table of chords, and in the course of the book he
gave many examples of how to use the table to find unknown parts of
triangles from known parts. Ptolemy provided what is now known as
Menelaus's theorem for solving spherical triangles, as well, and for
several centuries his trigonometry was the primary introduction to the
subject for any astronomer. At perhaps the same time as Ptolemy,
however, Indian astronomers had developed a trigonometric system based
on the sine function rather than the chord function of the Greeks."

For reference to the earliest written evidence for the development of
a trigonometric table see Asger Aaboe, Episodes From The Early History
of Mathematics, p. 111.

The Earliest Trigonometric Table?

If you have any clarifications, please don't hesitate to ask.

Thank you for using this service and have a nice day.

Warm regards,
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