Answer: (√6-√2)/4.
- A (√6-√2)/4
- B (√6+√2)/4
- C (√3-1)/2√2
- D (√3+1)/2√2
Correct answer: A. (√6-√2)/4
Explanation: sin 15° = sin(45°-30°) = sin45°cos30° - cos45°sin30° = (√2/2)(√3/2) - (√2/2)(1/2) = (√6-√2)/4.
Unit circle with standard angles 0, 30, 45, 60, 90 degrees; at 45 degrees the point is (cos45, sin45) = (1/sqrt2, 1/sqrt2).
Concept context
Ratios, identities, and applications in triangles