вычислите (sin 3п/4 - cos 5п/4) * sin (-0.5п) : cos (-7п/3)
(sin 3п/4 - cos 5п/4) * sin (-0.5п) : cos (-7п/3)=(sqrt{2}/2+sqrt{2}/2)*(-1)/1/2=-sqrt{2}/1/2=-2sqrt{2}