Question

Упростите:
$frac{2sin alpha -sin2 alpha }{cos alpha -1}$

Answer 1

$frac{2sin alpha -sin2 alpha }{cos alpha -1} =frac{2sin alpha -2sin alpha cos alpha }{cosalpha-1}=frac{2sinalpha(1-cosalpha)}{cos alpha -1}=-2sinalpha$

Answer 2

$frac{2sin alpha -sin2 alpha }{cos alpha -1} = frac{2sin alpha -2sin alpha cos alpha }{cos alpha -1}=frac{2sin alpha(1 -cos alpha) }{cos alpha -1}=frac{-2sin alpha(cos alpha-1) }{cos alpha -1}$$=-2sin alpha$