don't know how detailed your "unit circle" is , but you should easily read off that
sin30° = 1/2
cosπ = -1
sin 11π/6 = sin 330° = - sin30° = -1/2
cos 135 = -cos 45 = -√2/2
use the unit circle to determine the exact value of each angle: sine 30 degrees, cosine pi, sine 11 pi divided by 6, and cosine 135 degrees.
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