Тригонометрия. 10 класс.

420sin (-330°)=-sin330°=-sin (360°-30°)=sin30°=1/2=0,5cos(-120°)=cos120°=cos(180°-60°)=-cos60°=-1/2=-0,5tg(-240°)=-tg240°=-tg(180°+60°)=-tg60°=-√3ctg(-330°)=-ctg 330°=-ctg(360°-30°)=-ctg30°=-√3Поэтому ответ в задании 0,5²-(-0,5)²-(-√3)²+(-√3)²=0421sin(π/2 - α)=cosαcos( π  - α)=-cosαtg( π  -  α)= - tgαctg(3π/2  +α)=- tgαОтвет  cosα-(-cosα)-tgα-(-tgα)=2cosα422cos(-5π/6)=cos(5π/6)=cos(π  -   π/6)=-cosπ/6cos(11π/6)=cos (12π/6  - π/6)=cosπ/6tg(5π/6)=-tgπ/6=-√3.3sin(5π/3)=sin(π  + 2π/3)=- sin2π/3=-sinπ/3=-√3/2cosπ=-1cos(-4π/3)=cos(4π/3)=cos(π + π/3)=-cosπ/3=-1/2ctg2π/3=ctg(π   -  π/3)=-ctgπ/3=-√3/3 Ответ   -1 - (-√3/3)·(-√3/2)/(-1)+(-1/2)·(-√3/3)=-1+1/2+√3/6=1/2+√3/6=(3+√3)/6