Re: History of trigonometry

In article
<2386070.1166882761600.JavaMail.jakarta@xxxxxxxxxxxxxxxxxxxxxx>,
zeros <nimzeros@xxxxxxxxx> wrote:

....
When did someone define the sine of an angle greater than 90 degrees?

I think this may be happened in 17c. But I can't find any record about my
question....


It's an interesting question, which most popular historians of
mathematics scarcely mention.

The trigonometric functions defined for all real numbers (angles),
and the fact that those functions are periodic, are clearly treated in
Euler's classic "Introductio in Analysin Infinitorum" (1748). There's
an English translation by John D. Blanton, but I haven't been to our
library to look at it. My guess (and it's only a guess) is that Euler
was probably the first to use general angles in this way, although
possibly someone earlier may have considered positive obtuse angles
(between 90 and 180 degrees).

Ken Pledger.
.

Relevant Pages

  • Re: Trigonometric functions in Degrees
    ... ??>>> The trigonometric functions atre in radians. ... ??>>> take the trigonometric functins of angles in degrees? ... it might be noted that the RADIANS function exists so that SIN) = 0.5 etc. ...
    (microsoft.public.excel.misc)
  • Re: My proof that God exists (please read)
    ... On Wed, 28 Dec 2005, Mark VandeWettering wrote: ... >>> So Paul, I want to be absolutely certain that you're going to ... >> I believe in angles. ... If x is a sine of His will, then His will = arcsine x. ...
    (talk.origins)
  • Re: Binary degrees?
    ... No. Radians are the natural units for trig functions. ... The Taylor expressions for sine and cosine are in terms of angles expressed ...
    (sci.math)
  • Re: When is cos(x) rational?
    ... the the cosine of the angle VCV' ... rational (it seems to combine cases - if the sine or cosine is rational so ... rational multiple of pi, z is a root of one and so its mimimal polynomial ... The only angles which are a rational number of degrees (the same as a ...
    (sci.math)
  • Re: Hawking and distance of stars
    ... >>> You're a pip for figuring the angles. ... >> It's a sine of the times. ... >> DJT ...
    (talk.origins)