1. Limited time only! Sign up for a free 30min personal 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!

Arcsec problem [trigonometry]

  1. Feb 15, 2009 #1
    1. The problem statement, all variables and given/known data

    arcsec([2 * sqrt(3)] / 3)


    2. Relevant equations
    N/A


    3. The attempt at a solution
    I know that this is equivalent to saying sec (theta) = [2 * sqrt(3)] / 3
    I don't know how to solve for theta in terms of PI.

    I know sec = hyp/adj and the opp side I found was sqrt(3).
    When I try to do this in the calculator I get a DOMAIN error, and even if I did get an angle it would not be a whole number, how to I convert this in terms of PI?
     
  2. jcsd
  3. Feb 15, 2009 #2

    rock.freak667

    User Avatar
    Homework Helper

    If [itex]sec\theta= \frac{2\sqrt{3}}{3}[/itex]
    That means that cos[itex]\theta[/itex] = ?

    Also note that [itex]\frac{\sqrt{3}}{3}=\frac{1}{\sqrt{3}}[/itex]
     
  4. Feb 15, 2009 #3
    Yeah, I know cos (theta) = sqrt(3)/3 but I don't know how to find the angle. All the unit circles I see don't give that reference.
     
  5. Feb 16, 2009 #4

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    No, you do NOT "know cos (theta) = sqrt(3)/3"! What happened to the 2 in "[2 * sqrt(3)] / 3"?

    If [itex]sec(\theta)= \frac{2\sqrt{3}}{3}[/itex] then [itex]cos(\theta)= \frac{3}{2\sqrt{3}}[/itex]
    NOW use what rock.freak667 said.
     
    Last edited: Feb 16, 2009
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Arcsec problem [trigonometry]
  1. Trigonometry problem (Replies: 2)

  2. A Trigonometry Problem (Replies: 15)

  3. Trigonometry Problem (Replies: 3)

Loading...