Detailed description

  1. Circle with radius of 1, centre of circle the origin. Angle theta shown in first quadrant and angle pi plus theta in the third quadrant and 2pi minus theta in the fourth quadrant.
  2. Graph of y = sin theta to the right with, points marked at (0, 0), (theta, 0), (pi + theta, 0), (pi, 0), (2pi - theta, 0), (2pi, 0).