For this case, the first thing you should do is to know the following transformation: pi radians = 180 degrees Applying the transformation we have: (13pi / 6) * (180 / pi) = 390 degrees Then, in quadrant 1 we have: 390 - 360 = 30 degrees Answer: 13 pi / 6 as a function of an angle in quadrant i is: 30 degrees