Geometry

Question Analysis  

The main focus is to determine the coordinates on the unit circle for the angle using and , considering its position in the third quadrant.  

 

Key Concept Explanation  

On the unit circle, coordinates for an angle are given by . For (in QIII), both and are negative. The reference angle is .  

 

Step-by-Step Solution  

1. Find the reference angle:  

Reference angle = .  

2. Apply quadrant signs:  

In QIII: , .  

3. Use values: