Question

Помогите, пожалуйста (№1)

Answer 1

$-2sin alpha cos alpha -\\ frac{sin^3alpha -cos^3 alpha -3sin^2 alpha *cos alpha +3sinalpha *cos^2 alpha }{sin alpha -cos alpha } =-2sinalpha cos alpha = frac{(sinalpha -cosalpha )^3}{sin alpha -cos alpha } =\\=-2sinalpha cosalpha -(sinalpha -cosalpha )^2=\\= -2sinalpha cosalpha -(sin^2alpha -2sinalpha cosalpha+cos^2alpha )=\\ =-2sinalpha cosalpha +2sinalpha cosalpha -1=-1$