Question

Помогите с тригонометрией!!

Answer 1

Подробный разбор в приложении

Answer 2

$frac{-2sin(frac{13}{2}alpha)sin(-frac{alpha}{2})-2sin(frac{17}{2}alpha)sin(frac{alpha}{2})}{2cos(frac{13}{2}alpha)sin(-frac{alpha}{2})+2cos(frac{17}{2}alpha)sin(frac{alpha}{2})}$=$frac{sin(frac{13}{2}alpha)sin(frac{alpha}{2})-sin(frac{17}{2}alpha)sin(frac{alpha}{2})}{cos(frac{17}{2}alpha)sin(frac{alpha}{2})-cos(frac{13}{2}alpha)sin(frac{alpha}{2})}=frac{sin(frac{13}{2}alpha)-sin(frac{17}{2}alpha)}{cos(frac{17}{2}alpha)-cos(frac{13}{2}alpha)}$=$frac{-2cos(frac{15}{2}alpha)sinalpha}{-2sin(frac{15}{2}alpha)sinalpha}=ctg(frac{15}{2}alpha)$