Question

УПРОСТИТЬ ВЫРАЖЕНИЕ:

Answer 1

$frac{sina}{1+cosa} +frac{sina}{1-cosa} = frac{2sinfrac{a}{2}cdot cosfrac{a}{2}}{2cos^2frac{a}{2}}+frac{2sinfrac{a}{2}cdot cosfrac{a}{2}}{2sin^2frac{a}{2}} =\\= frac{sinfrac{a}{2}}{cosfrac{a}{2}} +frac{cosfrac{a}{2}}{sinfrac{a}{2}} =tgfrac{a}{2} +ctgfrac{a}{2}$

Answer 2

...=(sina*(1-cosa+1+cosa))/1-cosa^2=sina*2/sina^2=2sina/sina^2=2/sina