Question

1/1-tga-1/1+tga при a = pi/8
Помогли пожалуйста

Answer 1

$frac{1}{1-tgalpha}-frac{1}{1+tgalpha}=frac{1+tgalpha-1+tgalpha}{(1-tgalpha)(1+tgalpha)}=frac{2tgalpha}{1-tg^{2}alpha}= tg2alpha\\alpha=frac{pi}{8}Rightarrow tg2alpha=tg(2*frac{pi}{8})=tgfrac{pi}{4}=1$