Question

Evaluate : sin 15, cos15 ,tan 15

Answer 1

i assume u mean 15degree here and not radian
we know that sin(a-b)=sin a*cos b-cos a*sin b
now apply it for sin(45-30)
similarly we hv cos(a-b)=cos a*cos b+sin a*sin b
tan 15 can be calculated by sin15/cos 15