Question

упростить (cosa/1+sina+cosa/1-sina)*sin2a

Answer 1

$( \frac{cosa}{1+ sina} + \frac{cosa}{1-sina} )*sin2a=$$\frac{cosa(1-sina)+cosa(1+sina)}{(1+sina)(1-sina)}=$$\frac{2cosa*sin2a}{cos^2a} = \frac{2cosa*2sinacosa}{cos^2a} = 4 sina$