Question

помогите, срочно!
$sqrt{( cot {}^{2} a - tan{}^{2}a ) times cos2a } times tan(2a)$
спростить выражение если :
$frac{pi}{4} < a < frac{pi}{2}$
​

Answer 1

$sqrt{(Ctg^{2}alpha-tg^{2}alpha)*Cos2alpha}*tg2alpha=sqrt{frac{1}{Sin^{2}alpha}-1-frac{1}{Cos^{2}alpha}+1)*Cos2alpha} *tg2alpha =sqrt{frac{Cos^{2}alpha-Sin^{2}alpha}{Sin^{2}alpha*Cos^{2}alpha}*Cos2alpha} *tg2alpha=$

=$sqrt{frac{Cos^{2}2alpha}{Sin^{2}alpha*Cos^{2}alpha}}*tg2alpha=frac{-Cos2alpha}{Sinalpha Cosalpha}*frac{Sin2alpha}{Cos2alpha}=-frac{2Sin2alpha}{2Sinalpha Cosalpha}=-frac{2Sin2alpha}{Sin2alpha}=-2$

Answer 2

Ответ:  во вложении Объяснение: