trig
posted by BreAnne .
What is cos(11pi/3)? Explain your thinking.
What is sin(13pi/4) ? Explain your thinking.

3 2/3 pi
3 pi ends up at 180 degrees (2 pi + pi)
2/3 pi = 120 degrees
180 + 120 = 300 = 360  60
so 60 degrees below x axis in quadrant 4
cos 60 = 1/2
so
cos (11 pi/3) = 1/2
Now you do any more like that.