Answer#2

            a) In the picture below, the triangle has angle  (  ) .

So it is equilateral and the altitude (vertical line) splits the base in half .

So  

            b) Since , we reach the point  by going past  for one full revolution – which brings us back to the same point.

So,      

            c) Since  the triangle in the picture has  angles and since the hypotenuse is 1 each of the other two sides is of length . So  and   

            d) Since , 1 radian is just a bit less than  (actually about  ).

So cos(1)  is just a bit more than .5 (as can be seen from the left picture below).

            e) Note that one revolution is about 6 radians, so 30 radians corresponds to about 5 revolutions. But 5 full revolutions is actually  radians, and , so by going all the way to  we will have gone too far. Since, . So  is found by going back (clockwise) a distance of about 1.4 units ; and since 1.4 is a bit less than ,  is just a bit to the right of  .   So  (see right picture above).