How do you find the exact value of sin15degrees no decimalsS

How do you find the exact value of sin(15degrees) no decimals.

Solution

sin(15^o)

=sin(45^o-30^o)

sin(A-B)=sinAcosB-cosAsinB

=sin(45^o)cos(30^o) -cos(45^o)sin(30^o)  

=(1_/2)((3)_/2) -(1_/2)(1_/2)

=((3) -1)_/(22)