Question

Kto znayes etot ? pojalustaa pomogite

Answer 1

$tg2 alpha = frac{2*tg alpha }{1- tg^{2} alpha }$
$frac{2}{ frac{1}{tg frac{ pi }{8} }-tg frac{ pi }{8} } =2:( frac{1- tg^{2} frac{ pi }{8} }{tg frac{ pi }{8} } )= frac{2*tg frac{ pi }{8} }{1- tg^{2} frac{ pi }{8} } =tg(2* frac{ pi }{8} )=tg frac{ pi }{4}=1$