Answer:
sqrt(2-sqrt(3))/2
Explanation:
sin(15)=sin(30/2)=sqrt(1-cos(x))/sqrt(2)=(1-sqrt(3)/2)/sqrt(2)
Again we don't like compound fractions so multiply top and bottom inside sqrt( ) by 2.
sin(15)=sqrt(2-sqrt(3))/sqrt(4)
simplify
sin(15)=sqrt(2-sqrt(3))/2