Question

Упростить (тригонометрия)​

Answer 1

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