sin40 2 sin20 cos20
= = 2cos20
sin20 sin20
sin2t 2sintcost
- sint = - sint = 2sint - sint = sint
cost cost
sin40 2 sin20 cos20
= = 2cos20
sin20 sin20
sin2t 2sintcost
- sint = - sint = 2sint - sint = sint
cost cost