Cos 15° sin 75° menggunakan rumus cos A sin B

cosAsinB=1/2(sin(A+B)-sin(A-B))
cos15°sin75°=1/2(sin(15+75)°-sin(15-75)°)
=1/2(sin(90°)-sin(-60°))
=1/2(1+1/2√3)
=1/2((2+√3)/2)
= (2+√3)/4