Calculus help please?!

If the terminal side of 'theta' is in quadrant II and the reference angle is pi/3,

find the exact values of sin(theta) and cos(theta)

II. Quadrant : $\cos(\theta) <0 \\ \sin(\theta) >0$

So the answer is c.

$\begin{array}{|rcll|} \hline \sin^2(\theta) + \cos^2(\theta) &=& 1 \\ \left( \frac{\sqrt{3}}{2} \right)^2 + \left( -\frac12 \right)^2 &=& 1 \\ \frac{3}{4} + \frac14 &=& 1 \\ 1 &=& 1 \\ \hline \end{array}$