Question

очень срочно нужен номер 776

Answer 1

$1); ; 1+sin(pi - beta )cos(frac{3pi}{2}- beta )=1+sin beta cdot (-sin beta )=1+sin^2 beta \\2); ; 1+tg beta cdot tg2 beta =1+frac{sin beta cdot sin2 beta }{cos beta cdot cos2 beta }= frac{cos beta cdot cos2 beta +sin beta cdot sin2 beta }{cos beta cdot cos2 beta } =\\= frac{cos(2 beta - beta )}{cos beta cdot cos2 beta } =frac{1}{cos2 beta }\\3); ; 1-tg(frac{3pi}{2}- beta )ctg(frac{pi}{2}- beta )=1-ctg beta cdot tg beta =1-1=0$

$4); ; ctg alpha -ctg2 alpha = frac{cos alpha }{sin alpha } - frac{cos2 alpha }{sin2 alpha } = frac{cos alpha cdot sin2 alpha -cos2 alpha cdot sin alpha }{sin alpha cdot sin2 alpha } =\\= frac{sin(2 alpha - alpha )}{sin alpha cdot sin2 alpha } =frac{1}{sin2 alpha }$