Eduprobe
Question:
Express sin67° + cos75° in terms of trigonometric ratios of angles between 0° and 45°.
Solution:
sin67° + cos75° = sin(90° - 23°) + cos(90° - 15°)
[cos(90° - θ) = sinθ, sin(90° - θ) = cosθ]
= cos23° + sin15°
sin67° + cos75° = sin(90° - 23°) + cos(90° - 15°)
[cos(90° - θ) = sinθ, sin(90° - θ) = cosθ]
= cos23° + sin15°