Results 1 to 3 of 3

Math Help - Need help on figuring out some values

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    1

    Need help on figuring out some values

    Just need a quick recap of certain things. Explanation has to be without the use of a calculator.

    Using the unit circle, how do I find the sin and cos of pi/3.
    Using the unit circle, how do I find the sin and cos of pi/6.
    (I know the two have opposite cos and sin values, I just literally need to know how to get them without the use of a calculator but instead with the unit circle and the triangles.)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,110
    Thanks
    2
    Memorization.

    Were you expecting something a little more magic?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member nikhil's Avatar
    Joined
    Jun 2008
    Posts
    292

    Lightbulb lookkkkk!!

    draw x and y coordinate axis
    make the origin, the centre of circle (let it be o)
    now draw a unit circle. let it x intercepts be a and -a
    now raise the line segment oa at an angle of pi/3. drop a perpendiculat at x axis.
    let point of intersection be c. since cosx=length of base/length of hypotenuse
    but here hypotenuse =1 unit due to unit circle therefor
    cosx=length of base therefor
    cos(pi/3)=length of line segment oc=1/2
    but this method is not actually useful as its not possible to measure the length of line every time for example value of cos(pi/6)=sqrt[3]/2 here sqrt[3] is an irrational number which is non terminating and non recurring so one will never be able to measure this length accurately.
    for using them you may use other method for calculating values of sin,tan etc (not all values only for pi/2,pi/3,pi/4,pi/6, value for other angles can also be obtained but these values are elementary so can be obtained very easily using geometry)
    or you may just memorize it
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Figuring out x and y values in a constraint
    Posted in the Algebra Forum
    Replies: 3
    Last Post: April 30th 2010, 01:09 PM
  2. volume: figuring out integration values.
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 21st 2009, 08:57 AM
  3. Figuring out PMF's. HELP!
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: September 28th 2008, 03:04 PM
  4. need help for figuring out equation
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: November 13th 2007, 08:48 PM
  5. figuring out the age
    Posted in the Math Topics Forum
    Replies: 4
    Last Post: July 6th 2006, 02:11 PM

Search Tags


/mathhelpforum @mathhelpforum