2015 · Q70
The value of ²67^{}+²57^{}-²33^{}-²23^{} is
Elementary MathematicsTrigonometry
- A2{2}
- B2
- C{2}
- D0
Explanation
sin67° = cos23° and cos57° = sin33°, so sin²67° + cos²57° − sin²33° − cos²23° = cos²23° + sin²33° − sin²33° − cos²23° = 0 (option D). Stored key corrected from A to D.