Find the exact value of sin15 degree Find the exact value of

Find the exact value of sin(15 degree). Find the exact value of sin(105 degree). Find the exact value of sin (255 degree).

1. Sin 15=sin(45-30)

=sin 45 cos 30 -cos 45 sin 30

=(1/sqrt2)(sqrt3/2)-(1/sqrt2)(1/2)

=(sqrt 3 -1)/(2sqrt2)

2. Sin 105=sin(60+45)=sin 60 cos 45+cos 60 sin45

=(sqrt3 +1)/(2sqrt2)

3. Sin 255=sin(300-45)=sin300 cos 45-cos 300sin45

=(-sqrt3 -1)/(2sqrt2)