Question

Упростите выражение:

Answer 1

$frac{cos alpha (1-sin alpha)-cos alpha (1+sin alpha )}{(1+sin alpha )(1-sin alpha )} = frac{(cos alpha )(1-sin alpha -1-sin alpha )}{1- sin^{2} alpha } = frac{(cos alpha )(-2sin alpha )}{cos^{2} alpha } =$
$-frac{2sin alpha }{cos alpha } =-2tg alpha$