Өрнекті ықшамда: sin(2π/15)cos(π/5) + cos(2π/15)sin(π/5)

sin(2π/15)cos(π/5)+cos(2π/15)sin(π/5) = = sin (2π/15 + π/5) = = sin ( 2π/15 + 3π/15) = sin (5π/15) = sin (π/3) = √3/2