Вычислите а) tg 21PI/4 б) sin 11PI/6 в) cos (- 2PI/3)

Question

Вычислите
а) tg 21PI/4 б) sin 11PI/6 в) cos (- 2PI/3)

Answer 1

A)tg21π/4=tg(5π+π/4)=tgπ/4=1
б)sin11π/6=sin(2π-π/6)=sin(-π/6)=-sinπ/6=-1/2
в)cos(-2π/3)=cos2π/3=cos(π-π/3)=-cosπ/3=-1/2