Find the Point $( x , y )$ On the Unit Circle That Corresponds to the Real Number

Multiple Choice

Find the point $( x , y )$ on the unit circle that corresponds to the real number $\frac { 5 \pi } { 6 }$ .Use your results to evaluate $\cos t$ .

A) $\cos t = \frac { \sqrt { 3 } } { 2 }$
B) $\cos t = - \frac { \sqrt { 3 } } { 2 }$
C) $\cos t = - \frac { 1 } { 2 }$
D) $\cos t = - 1$
E) $\cos t = 1$