cos156sin(-350)ctg230=cos(180-24)sin(10)ctg(50)=-cos24sin10ctg50<0
cos13П/15ctg2П/18=cos(П-2П/15)ctg(П/9)=-cos2П/15ctgП/9<0
cos156sin(-350)ctg230=cos(180-24)sin(10)ctg(50)=-cos24sin10ctg50<0
cos13П/15ctg2П/18=cos(П-2П/15)ctg(П/9)=-cos2П/15ctgП/9<0