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Homework Help: Trigonometry Question (Trigonometric Functions)

  1. Nov 15, 2011 #1
    1. The problem statement, all variables and given/known data

    Hello again, not looking for anyone to solve this problem this time I just need to know what the operation I'm supposed to do is called, so I can go research it and learn it.

    If sin(t) = -12/13 with 3pi/2 < t < 2pi, find the following:

    b) cos(t - 11pi/6)

    2. Relevant equations

    I'm assuming this is a trigonometric function that is about graphing these things. But I'm not sure. >_<

    3. The attempt at a solution

    As I said, I'm not looking for the solution. Just what kind of operation this is.
  2. jcsd
  3. Nov 15, 2011 #2


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    Homework Helper

    Use sin2x + cos2x = 1 to find cos(t). Then, use the cosine of a difference identity to evaluate cos(t - 11pi/6).
  4. Nov 15, 2011 #3
    Oh, it's a sum and difference equation. My bad. I will go work on this now...
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