sin(240) = -√(3)/2
sin(240) = 2sin(120)cos(120)
sin(240) = 2[2sin(60)cos(60)cos(120)]
sin(240) = 2[2[2sin(30)cos(30)cos(60)cos(120)]]
sin(240) = 2[2[2[2sin(15)cos(15)cos(30)cos(60)cos(120)]]]
sin(240) = 16sin(15)cos(15)cos(30)cos(60)cos(120)
cos(240) = ⁻¹/₂
cos(240) = cos¹⁶(15) - sin¹⁶(15)