Question

pomogite 3 zadachu rewit...

Answer 1

Сделаем замену 
$arcsin(-frac{1}{4})= alpha$
тогда 
$tg(alpha+90а)=ctg alpha \ ctg alpha =frac{cos alpha }{sin alpha }$
а так как $cos(arccos beta )= beta$ то 


$frac{cos alpha }{sin alpha } = frac{cos(arcsin-frac{1}{4})}{sin(arcsin-frac{1}{4})}\ sina=-frac{1}{4}\ cosa=sqrt{1-frac{1}{4}^2}=frac{sqrt{15}}{4}\ ctga=frac{frac{sqrt{15}}{4}}{frac{1}{4}}=sqrt{15}$
Ответ  $sqrt{15}$