Question

Решите, пожалуйста (;

Answer 1

$x=tgfrac{5pi}{6}=tg(pi -frac{pi}{6})=-tgfrac{pi}{6}=-frac{1}{sqrt3}approx -0,58\\y=cosfrac{2pi}{5}=cos72^circ textgreater 0; ,; t.k.; ; 72^circ in (0,90^circ )\\z=tg(-frac{pi}{8}) =-tgfrac{pi}{8}=- frac{1-cosfrac{pi}{4}}{sinfrac{pi}{4}} =- frac{1-frac{sqrt2}{2}}{frac{sqrt2}{2}} =-frac{2-sqrt2}{sqrt2}=\\=1-sqrt2approx -0,41\\y textgreater z textgreater x$