sin (-5п/9)cos 7п/4 tg (-п/4)=-sin (5п/9)*cos(п+ 3п/4)*(-1)=-sin (5п/9)*cos(3п/4)=-sin (5п/9)* (-√2/2)=√2*sin (5п/9) /2
ответ:+
sin (-5п/9)cos 7п/4 tg (-п/4)=-sin (5п/9)*cos(п+ 3п/4)*(-1)=-sin (5п/9)*cos(3п/4)=-sin (5п/9)* (-√2/2)=√2*sin (5п/9) /2
ответ:+