Question

Express (sin 67° + cos 75°) in terms of trigonometric ratios of the angle between 0° and 45°.

Answer 1

(sin 67° + cos 75°)
= (sin (90°−23°) + cos (90°−15°))      .....(∵ sin(90°−θ) = cosθ and cos(90°−θ) = sinθ)
= (cos 23°+ sin 15°)