Question 960505
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)
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cos(-pi/6) = cos(pi/6)
= sqrt(3)/2