Question

УПРОСТИТЬ ВЫРАЖЕНИЕ:

Answer 1

$\frac{sina}{1+cosa} +\frac{sina}{1-cosa} = \frac{2sin\frac{a}{2}\cdot cos\frac{a}{2}}{2cos^2\frac{a}{2}}+\frac{2sin\frac{a}{2}\cdot cos\frac{a}{2}}{2sin^2\frac{a}{2}} =\\\\= \frac{sin\frac{a}{2}}{cos\frac{a}{2}} +\frac{cos\frac{a}{2}}{sin\frac{a}{2}} =tg\frac{a}{2} +ctg\frac{a}{2}$

Answer 2

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