Question

поподробнее,пожалуйста

Answer 1

$frac{cos2alpha}{sinalpha}+frac{sin2alpha}{cosalpha}=frac{cos^2alpha-sin^2alpha}{sinalpha}+frac{2sin alpha cos alpha }{cosalpha}=frac{cos^2alpha-sin^2alpha}{sinalpha}+2sin alpha= \ = frac{cos^2alpha-sin^2alpha+2sin^2alpha}{sinalpha}=frac{cos^2alpha+sin^2alpha}{sinalpha}= frac{1}{sin alpha}$