Results 1 to 6 of 6

Math Help - What is the exact value of sin(pi/12)

  1. #1
    Senior Member
    Joined
    Nov 2008
    Posts
    425

    What is the exact value of sin(pi/12)

    What is the exact value of sin(pi/12)

    Explain how you get it
    Last edited by mr fantastic; August 12th 2009 at 04:30 PM. Reason: Put post title in main post as well.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Mar 2007
    Posts
    1,240

    Talking

    Quote Originally Posted by skeske1234 View Post
    Explain how you get it
    Explain how one gets what? There is no question in your post.

    Are you maybe referring to the contents of your subject line...? If so, then try using the same sort of technique which was provided to you here.

    If you get stuck, please reply showing how far you have gotten, starting with how you turned 1/12 into a sum or difference of 1/2, 1/3, 1/4, and / or 1/6, and showing which trig identity you are using. Thank you!
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Nov 2008
    Posts
    425
    I don't know what compound angle formula to use for
    sin(pi/12)
    because pi/12 = 15 degrees... There is no special angle that will add up to that.
    What is another method I could use?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Mar 2007
    Posts
    1,240

    Talking

    So try doing subtractions....
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Senior Member
    Joined
    Nov 2008
    Posts
    425
    Quote Originally Posted by stapel View Post
    So try doing subtractions....
    OHHHHHHHSDLKJGHDSKJGHSDJ omg . k.

    wow -.-
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Mar 2009
    Posts
    31
    Hello,

    U have this formula:

    sin^2(x)=\frac{1-cos(2x)}{2}\Rightarrow sin(x)=\sqrt{\frac{1-cos(2x)}{2}}

    sin(\frac{\pi}{12})=\sqrt{\frac{1-cos(\frac{\pi}{6})}{2}}

    sin(\frac{\pi}{12})=\sqrt{\frac{1-\frac{\sqrt{3}}{2}}{2}}



    Also u can have the next method

    sin(\frac{\pi}{4}-\frac{\pi}{6})=sin(\frac{\pi}{4})cos(\frac{\pi}{6}  )-sin(\frac{\pi}{6})cos(\frac{\pi}{4})

    sin(\frac{\pi}{4}-\frac{\pi}{6})=\frac{\sqrt{2}}{2}*\frac{1}{2}-\frac{\sqrt{3}}{2}*\frac{\sqrt{2}}{2}


    Have a nice day,

    Hush_Hush.
    Last edited by Hush_Hush; April 6th 2009 at 11:46 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 5
    Last Post: September 21st 2011, 12:12 AM
  2. to be exact or not exact? this is the question...
    Posted in the Differential Equations Forum
    Replies: 2
    Last Post: February 5th 2011, 08:56 AM
  3. Why are exact ODEs called exact?
    Posted in the Differential Equations Forum
    Replies: 6
    Last Post: December 27th 2009, 09:48 AM
  4. exact value
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 27th 2009, 04:40 PM
  5. Exact value of sin
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: October 9th 2008, 04:41 PM

Search Tags


/mathhelpforum @mathhelpforum