Question

Выражение 1-cosα + cos2α / sin2α - sinα

Answer 1

$1-cosa+ \frac{cos(2a)}{sin(2a)} -sina= \frac{2sin^3a+((-2)*cosa-2)sin^2a+(2cosa-2)*sina+1}{2cosa sina}$ =$\frac{-cos(2a))*(sin(3a)-cos(3a)-2sin(2a)-2cos(2a)+sina+cosa)}{2}$

Answer 2

$1-cos\alpha + \frac{cos2\alpha}{sin2\alpha}-sin\alpha = 1-2sin \frac{\alpha}{2}cos \frac{\alpha}{2}+ctg2\alpha= \\ =1-sin\alpha +ctg2\alpha= \frac{cos^2\alpha}{1+sin\alpha} +ctg2\alpha \\$