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Where did trig functions come from?

  1. Jan 3, 2005 #1
    I've been thought trig functions in school definitely, but never been told how were they invented in the first place! Also, is there a function like sin (theta)= something. If so, what are these functions?
  2. jcsd
  3. Jan 3, 2005 #2

    matt grime

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    "is there a function like sin (theta)= something."

    pardon? what do you mean 'like'? or something? sin is a function, it's like itself, it's 'like' a power series, is that what you mean?
  4. Jan 3, 2005 #3
    Check this History of Trigonometry.

    -- AI
    Another Reference : http://www.math.unifi.it/archimede/archimede_inglese/trigonometria/trigonometria/prima.html [Broken] but says the same thing.
    Last edited by a moderator: May 1, 2017
  5. Jan 4, 2005 #4
    thanks the history part was useful.

    to matt: actually what i meant was could I get a function while I substitute theta, I will get the result of sine theta without using my calculator to find sine theta of course.
  6. Jan 4, 2005 #5

    matt grime

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    Without using a calculator? OF course not. calculate the square of 3.45234232526 without one - takes a while agreed? calculate the square of the 5#th root of 2. this is of course a question about what you mean by calculate. in this case you mean find a decimal representation of. to what degree of accuracy?

    there are many ways to caculate sin, cos and many other functions as power series, called taylor or maclaurin series.

    [tex]\sin(x)= x - \frac{x^3}{3!} + \frac{x^5}{5!}- \frac{x^7}{7!} \ldots[/tex]

    terminate after as many terms as required.
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