1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Sin/Cos/Tan question

  1. Aug 17, 2004 #1
    I've been working with the trigonometric ratios for a long time now and was wondering, when you type sin(x), where x is any number and hit the equals sign, what function is actually being applied to the number?
     
  2. jcsd
  3. Aug 17, 2004 #2
    I guess that would be
    [tex]\sin(x)=\sum_n \left( \frac{x^{4n+1}}{(4n+1)!}-\frac{x^{4n+3}}{(4n+3)!} \right)[/tex]
    to finite order, by first reducing to the fundamental [tex] [-\pi;\pi] [/tex]
     
  4. Aug 17, 2004 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    For a very long time, I thought that calculators (and computers) used the Taylor's series (what humanino gives is a variation on that) for ex, sin(x), cos(x), etc. but I have been informed that all modern calculations use the "CORDIC" algorithm.

    Here is a link to an explanatory website:
    http://www.dspguru.com/info/faqs/cordic.htm
     
    Last edited: Aug 17, 2004
  5. Aug 17, 2004 #4
    now, that's clever ! Anyway, I had doubt about the series. Thanks Hallsoflvt. This algorithm makes me thinf of FFT.
    edit:
    (well actually it is much simpler)
     
  6. Aug 17, 2004 #5
    Interesting, thanks.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Sin/Cos/Tan question
  1. Sin cos tan (Replies: 16)

  2. Sin/cos/tan of theta (Replies: 8)

  3. Sin, Cos, Tan (Replies: 2)

  4. Sin/cos/tan by hand? (Replies: 2)

Loading...