Question

помогите срочно быстроо

Answer 1

$left ( frac{sin4 alpha }{cos alpha } + frac{cos4 alpha }{sin alpha } right )cdot left ( frac{1}{cos3 alpha } - frac{1}{cos alpha } right )=\\= frac{sin alpha cdot sin4 alpha +cos alpha cdot cos4 alpha }{cos alpha cdot sin alpha } cdot frac{cos alpha -cos3 alpha }{cos3 alpha cdot cos alpha } =\\= frac{-cos3 alpha }{frac{1}{2}sin2 alpha } cdot frac{2sin2 alpha cdot sin alpha }{cos3 alpha cdot cos alpha } =-4cdot frac{sin alpha }{cos} =-4tg alpha$