3sin13/12П * cos 13/12П
3sin13/12П * cos 13/12П= 3*2/2sin13/12П * cos 13/12П= =3/2*2sin13/12П * cos 13/12П = 3/2*Sin26/12π = 1,5Sin(2π + π/6) = = 1,5Sinπ/6 = 1,5 *1/2 = 0,75