2023 · Q50
What is the value of x that satisfies 4 cos² 30° + 2x sin 30° - cot² 30° - 6 tan 15° tan 75° = 0?
Elementary MathematicsTrigonometry
- A1
- B2
- C3
- D6
Explanation
4cos²30° = 4·(3/4) = 3, 2x sin30° = x, cot²30° = 3, and tan15°tan75° = tan15°cot15° = 1. The equation becomes 3 + x − 3 − 6 = 0, so x = 6 (D).