Question

Сократить. Картинка прилагается.

Answer 1

$displaystyle left(frac{cos^3alpha}{sinalpha}-frac{sin^3alpha}{cosalpha}right)cdot {rm tg},2alpha=left(frac{cos^4alpha-sin^4alpha}{sinalphacosalpha}right)cdot frac{sin2alpha}{cos2alpha}=\ \ \ =frac{2left(cos^2alpha-sin^2alpharight)left(cos^2alpha+sin^2alpharight)}{2sinalphacosalpha}cdotfrac{sin2alpha}{cos2alpha}=frac{2cos2alphacdot 1}{sin2alpha}cdotfrac{sin2alpha}{cos2alpha}=2$