SOLUTION: I know the points on the unit circle but how do I find for example: cos(11pi/6) My teacher hasn't cleared this up for me what are you suppose to do or know in order to break t

Question 960505: I know the points on the unit circle but how do I find for example:
cos(11pi/6)
My teacher hasn't cleared this up for me what are you suppose to do or know in order to break this number down further, I know it has something to do with either subtracting or adding 2pi or pi to the number but how do I know what to use and when? please give as much detail as you can I have a major exam coming up, I must know this stuff.
Thank you
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
I know the points on the unit circle but how do I find for example:
cos(11pi/6)
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11pi/6 is less than 2pi, so there's no adding or subtracting.
In degrees, it's 330, or -30 = -pi/6
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cos(-angle) = cos(angle)
---
cos(-pi/6) = cos(pi/6)
= sqrt(3)/2

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