Question

Помогите доказать тождество

Answer 1

$displaystyle frac{sinalpha+sin3alpha+sin5alpha}{cosalpha+cos3alpha+cos5alpha}=frac{2sin3alphacos2alpha+sin3alpha}{2cos3alphacos2alpha+cos3alpha}=\ \ \ =frac{sin3alpha(2cos2alpha+1)}{cos3alpha(2cos2alpha+1)}=frac{sin3alpha}{cos3alpha}=tt tg3alpha$

Answer 2

Спасибо большое