sin(-7pi/12)

= -sin(7pi/12)

= -sin(pi/4 +pi/3)

= -[sin(pi/4)cos(pi/3) +cos(pi/4)sin(pi/3)]

= -[(1/sqrt(2))(1/2) +(1/sqrt(2))(sqrt(3)/2)]

= -[1 /2sqrt(2) +sqrt(3) /2sqrt(2)]

= -(sqrt(2) /4)(1 +sqrt(3)) -----answer.

or,

= -(1/4)[sqrt(2) +sqrt(6)] ---------answer also