So, i figured out how to find the sine and cosine of ββ, but i wasn't sure how to complete the problem. do i find the sine of ββ and the sine of 2 separately then divide them? is it more or less complicated than that? for the !

Recall the half-angle identity:



So in order to find , we only need to know the value of . But there are two possible values. To decide which to take, we use the given information: we know that lies in quadrant III, which means , so , which places in quadrant II. In this quadrant, the sine of angle is positive, and so



is an angle of a ray whose terminal point, lies on the circle . The -coordinate is all we need to know in order to find that . So,