Question 1160122


using Half-Angle Identities

{{{sin(x/2) =  sqrt((1 - cos(x))/2)}}}

{{{sin(30/2) =  sqrt((1 - cos(30))/2)}}}...... {{{sin(30)=1/2}}}

{{{sin(15) =  sqrt((1 - sqrt(3)/2)/2)}}}

{{{sin(15) = (1/4)(sqrt(6) - sqrt(2))}}}


{{{cos(x/ 2)= sqrt((1+cos(x))/2)}}}

{{{cos(15)=sqrt((1+cos(30))/2)}}}.......{{{cos(30)= sqrt(3)/2}}}

 {{{cos(15)= sqrt((1+sqrt(3)/2)/2)}}}

{{{cos(15)=(1/4)(sqrt(2) + sqrt(6))}}}


{{{sin(15)cos(15)=(1/4)(sqrt(6) - sqrt(2))*(1/4)(sqrt(6) + sqrt(2))}}}}

{{{sin(15)cos(15)=(1/16)((sqrt(6))^2 - (sqrt(2))^2)}}}}

{{{sin(15)cos(15)=(1/16)(6 - 2)}}}}

{{{sin(15)cos(15)=(1/16)(4)}}}}

{{{sin(15)cos(15)=(1/cross(16)4)(cross(4))}}}}

{{{sin(15)cos(15)=1/4}}}