Решить пример (Sin13п/4-cos9п/4)*sin(-4,5п)

1)Вычислите а)sin 5п/4=sin(π-π/4)=sin π/4=√2/2 б)tg 7п/6=tg(π+π/6)=tg π/6=√3/3 в)cos п/6 - ctg π/4=√3/2-1г)tg 3п/4 x cos 3п/4+сtg(-п/6) х sin п/6=sin 3π/4/cos 3π/4*cos 3π/4-cosπ/6/sinπ/6*sinπ/6=sin 3π/4-cos π/6=sin(π-π/4)-cosπ/6=sinπ/4-cosπ/6=√2/2-√3/2 д)sin 510-sin270 ctg270=sin (2π+π-30)-sin 270*cos270/sin270=sin30-cos(2π-90)=1/2-1=-0.5