Geometry

Question Analysis  

The main focus is to determine which quadrant has a positive sine value ( > 0) and a negative cosine value ( < 0) by applying trigonometric sign conventions in each quadrant.  

 

Key Concept Explanation  

In the unit circle, the signs of (y-coordinate) and (x-coordinate) depend on the quadrant:  

QI: x > 0, y > 0 →  > 0,  > 0.  

QII: x < 0, y > 0 →  < 0,  > 0.  

QIII: x < 0, y < 0 →  < 0,  < 0.  

QIV: x > 0, y < 0 →

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