Question

Срочно!
Сразу большое спасибо ❤

Answer 1

$1);ctgx=frac{2sqrt5}5=frac{2sqrt5}{sqrt5cdotsqrt5}=frac2{sqrt5}\ctgx=frac1{tgx}=frac1{frac{sqrt5}2}=frac2{sqrt5}\\2);cosalpha=0,9\sinalpha=sqrt{1-cos^2alpha}=sqrt{1-0,81}=pmsqrt{0,19}\0<alpha<fracpi2Rightarrowsinalpha>0\sinalpha=sqrt{0,19}\tgalpha=frac{sinalpha}{cosalpha}=frac{sqrt{0,19}}{0,9}\ctgalpha=frac{cosalpha}{sinalpha}=frac{0,9}{sqrt{0,19}}$