Results 1 to 2 of 2

Thread: Special Identities - troubles rationalizing

  1. #1
    Junior Member
    Sep 2008

    Special Identities - troubles rationalizing

    I'm currently studying for my upcoming precalculus midterm, but I'm having troubles rationalizing denominators and simplifying--and I'm not sure if I'm approaching this correctly. If anyone could lend me pointers to simplify please let me know, I'm really weak in this area.

    Use a sum or difference formula to find the exact value of the given expression:

    $\displaystyle \sin \frac{7\pi}{12}$
    I figured...
    $\displaystyle \frac{\pi}{4} + \frac{\pi}{3}=\frac{7\pi}{12}$
    Thus according to the values...
    $\displaystyle \frac{\sqrt2}{2}\times\frac{\sqrt2}{2}+\frac{\sqrt 3}{2}\times\frac{1}{2}$

    I totally got the wrong answer from here. How should I go about simplifying this?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Oct 2005
    So we have $\displaystyle \frac{\sqrt2}{2}\times\frac{\sqrt2}{2}+\frac{\sqrt 3}{2}\times\frac{1}{2}$

    Order of operations says multiply before adding so let's multiply everything together we can.

    $\displaystyle \frac{\sqrt{2}*\sqrt{2}}{2*2}+\frac{\sqrt{3}*1}{2* 2}$

    $\displaystyle \frac{2}{4}+\frac{\sqrt{3}}{4} = \frac{2+\sqrt{3}}{4}$
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Rationalizing
    Posted in the Algebra Forum
    Replies: 1
    Last Post: Sep 14th 2011, 07:01 AM
  2. [SOLVED] Newton's Method special case troubles....
    Posted in the Calculus Forum
    Replies: 11
    Last Post: Feb 7th 2011, 04:36 PM
  3. Trig identities with special triangles
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: Nov 15th 2010, 10:43 PM
  4. Replies: 3
    Last Post: Nov 13th 2008, 07:39 PM
  5. 2 Special identities questions..
    Posted in the Calculus Forum
    Replies: 1
    Last Post: Nov 11th 2008, 01:37 AM

Search Tags

/mathhelpforum @mathhelpforum