Answer: (√6 + √2)/4.
- A (√6 + √2)/4
- B (√6 − √2)/4
- C (√3 + 1)/2
- D 1/2
Correct answer: A. (√6 + √2)/4
Explanation: sin 75° = sin(45° + 30°) = (√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