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!

Trigonometry Question

  1. Sep 15, 2004 #1


    User Avatar

    How do I do this? Thanks.
  2. jcsd
  3. Sep 15, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper

    recall the emanings, with a picture, of these functions sin, cos, tan, using a unit circle. you may be able to just see it.
  4. Sep 16, 2004 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    Do you know that sin2(θ)+ cos2(θ)= 1? Since you know sin(θ)= 1/3, you can use that to find cos(θ). Now, how is tan(θ) defined?
  5. Sep 16, 2004 #4
    Take the arc sin of 1/3 - this will give you the angle, but it will be the principle angle (first quadrant). But, since Cos theta <0, you know it can't be in the first quadrant or fourth quadrant, so it must be in either the second or third quadrant. But, since sin theta is >0, it must be in the second quadrant. You should be able to get the correct angle from this info, and therefore the correct cosine and then - as was hinted before - remember the definition of tangent theta.
  6. Sep 17, 2004 #5


    User Avatar

    I got it now, Thanks guys :)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Trigonometry Question
  1. Trigonometry question (Replies: 3)

  2. Trigonometry Question (Replies: 7)