Question

Express each of the following in terms of trigonometric ratios of angles lying between 0° and 45°.

sin67° + cos75° 

Answer 1

\[\sin67^\circ + \cos75c\]
\[ = \cos\left( 90^\circ - 67^\circ \right) + \sin\left( 90^\circ - 75^\circ \right)\]
\[ = \cos23^\circ + \sin15^\circ\]