Question

Пожалуйста Помогите
1) Sin 5п/6 - sin п/6=
2) -cos 2п/3 - (- cos п/3)=

Answer 1

Sin 5п/6 - sin п/6=sin(π-π/6)-sinππ/6=sinπ/6-sinπ/6=0
-cos 2п/3 - (- cos п/3)=-cos(π-π/3)+cosπ/3=cosπ/3+cosπ/3=1/2+1/2=1