Express $\sin 67^{\circ}+\cos 75^{\circ}$
Question.
Express $\sin 67^{\circ}+\cos 75^{\circ}$ in terms of trigonometric ratios of angles between $0^{\circ}$ and $45^{\circ}$.
Express $\sin 67^{\circ}+\cos 75^{\circ}$ in terms of trigonometric ratios of angles between $0^{\circ}$ and $45^{\circ}$.
Solution:
sin 67° + cos 75°
= sin(90° – 23°) + cos (90° – 15°)
= cos 23° + sin 15°
sin 67° + cos 75°
= sin(90° – 23°) + cos (90° – 15°)
= cos 23° + sin 15°