sin(61п/6) = sin(10п+п/6) = sin(п/6) = 1/2
cos(61п/6) = cos(10п+п/6) = cos(п/6) = (корень из 3)/2
sin(-52п/3) = -sin(52п/3) = -sin(17п+п/3) = -sin(16п+п+п/3) =-sin(п+п/3) =
=sin(п/3) = (корень из 3)/2
cos(-52п/3) =cos(52п/3) = cos(17п+п/3) = cos(16п+п+п/3) =cos(п+п/3) =
=-cos(п/3) = -1/2
https://studwork.ru/spravochnik/matematika/drobi/vychitanie-drobey
sin(61п/6) = sin(10п+п/6) = sin(п/6) = 1/2
cos(61п/6) = cos(10п+п/6) = cos(п/6) = (корень из 3)/2
sin(-52п/3) = -sin(52п/3) = -sin(17п+п/3) = -sin(16п+п+п/3) =-sin(п+п/3) =
=sin(п/3) = (корень из 3)/2
cos(-52п/3) =cos(52п/3) = cos(17п+п/3) = cos(16п+п+п/3) =cos(п+п/3) =
=-cos(п/3) = -1/2
https://studwork.ru/spravochnik/matematika/drobi/vychitanie-drobey