Results 1 to 5 of 5

Math Help - trigonometic

  1. #1
    Newbie
    Joined
    Jun 2008
    Posts
    18

    Exact value of trig functions

    How do you Find on a unit circle that corresponds to t = 5 π /6.

    and im also having trouble Finding the exact value of i dnt no how to get the exact value
    Last edited by topsquark; June 9th 2008 at 05:27 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,111
    Thanks
    2
    Think "Reference Angle". Look it up and show us what you get.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Behold, the power of SARDINES!
    TheEmptySet's Avatar
    Joined
    Feb 2008
    From
    Yuma, AZ, USA
    Posts
    3,764
    Thanks
    78
    Quote Originally Posted by missjky View Post
    Find on a unit circle that corresponds to t = 5 π /6.
    i dnt understand how you find the anwsr
    The function you want is

    \omega:[0,2\pi] \to \{(x,y)|x\in [-1,1]) \mbox{ and } y \in [-1,1]

    \omega(t)=(\cos(t),sin(t))

    \omega\left( \frac{5\pi}{6}\right)=(\cos\left( \frac{5\pi}{6}\right),\\sin\left( \frac{5\pi}{6}\right))=\left( \frac{-\sqrt{3}}{2},\frac{1}{2}\right)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Jun 2008
    Posts
    18
    Quote Originally Posted by TheEmptySet View Post
    The function you want is

    \omega:[0,2\pi] \to \{(x,y)|x\in [-1,1]) \mbox{ and } y \in [-1,1]

    \omega(t)=(\cos(t),sin(t))

    \omega\left( \frac{5\pi}{6}\right)=(\cos\left( \frac{5\pi}{6}\right),\\sin\left( \frac{5\pi}{6}\right))=\left( \frac{-\sqrt{3}}{2},\frac{1}{2}\right)
    thank you i understand now, so how do you Evaluate i no how to get it in decimal form but not in fraction form also

    Evaluate

    also whether f(x) = -sin x is even, odd, or neither but i think its neither is that correct
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Behold, the power of SARDINES!
    TheEmptySet's Avatar
    Joined
    Feb 2008
    From
    Yuma, AZ, USA
    Posts
    3,764
    Thanks
    78
    Quote Originally Posted by missjky View Post
    thank you i understand now, so how do you Evaluate i no how to get it in decimal form but not in fraction form also

    Evaluate

    also whether f(x) = -sin x is even, odd, or neither but i think its neither is that correct
    Remember that we can rewrite coterminal angles by adding (or subtracting ) multiples of 2 Pi.

    \frac{31\pi}{3}=10\pi+\frac{\pi}{3}

    The first tells us to go around the unit circle 5 times (10 Pi radians)and the Pi/3 more times so

    \frac{31\pi}{3}\mbox{ and }\frac{\pi}{3}

    Will have the same out put for trig functions.

     \cos\left( \frac{31\pi}{3}\right)= \cos\left( \frac{\pi}{3}\right)=\frac{1}{2}

    This diagram should help you discover that sine is an odd function.
    Take a look and see if you can convince yourself. If you have any more questions just ask.

    trigonometic-trig.jpg
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help! Proving trigonometic identities!
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: February 22nd 2010, 09:15 AM
  2. Help with 2 trigonometic equations?
    Posted in the Pre-Calculus Forum
    Replies: 7
    Last Post: May 4th 2009, 06:54 AM
  3. trigonometic funtions
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: June 9th 2008, 05:32 AM
  4. angles and trigonometic functions
    Posted in the Trigonometry Forum
    Replies: 11
    Last Post: June 8th 2008, 05:47 PM
  5. Trigonometic Identities
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: November 16th 2006, 08:05 PM

Search Tags


/mathhelpforum @mathhelpforum