Trigonometric functions of the unit cirlce

  1. I just came across a problem that wants you to solve for csc of an angle in radians... However, I'm confused about the answer given.

    Here is the problem:

    Find the csc when t=-2pi/3, which is equivalent to -120 degrees right?

    I got -2sqrt.(3)/3 but the answer in the back is -2sqrt.(3)/2 Why is it a 2 instead of a three??

    The sin is -sqrt.(3)/2 and it is correct, so shouldn't the csc be the reciprocal of sin?? 1/sin theta?? so 1/(-2sqrt.(3)/3)????????

    Thanks!
     
  2. jcsd
  3. cristo

    cristo 8,412
    Staff Emeritus
    Science Advisor

    Your book is wrong. [tex] cosec(\frac{-2\pi}{3}) = \frac{-2\sqrt{3}}{3} [/tex]
     
  4. wow... I think I've actually seen quite a few with 2's as the denominator. I'm pretty sure that I was right and the book was wrong. I'm astonished though, this book sucks! =/


    Thanks for helping me check btw!! =]
     
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