Question

sin(105 degrees) - sin(15 degrees)
and
sin(52.5 degrees)cos(7.5 degrees)

Answer 1

\[\sin C-\sin D=2\cos \frac{ C+D }{ 2 }\sin \frac{ C-D }{2}\]
\[2\sin C \cos D=\sin \left( C+D \right)+\sin \left( C-D \right)\]
Now you can solve the two questions.