1. The problem statement, all variables and given/known data For the value of cos θ, determine the radian value of θ if π ≤ θ ≤ 2π. Value is -1/2. 2. Relevant equations 3. The attempt at a solution I got the first value which is cos-1(-1/2) which I got (2π)/3. However I am unsure how to get the second value. I thought that since the first value is in second quadrant the other value is in the third quadrant, then I would take θ-π to find my value in the quadrant. But my answer was incorrect. Can someone pls guide me? Thx.