Question

Помогите пожалуйста с алгеброй
(3;4)

Answer 1

$tg alpha +tg beta = frac{sin alpha }{cos alpha } + frac{sin beta }{cos beta } = frac{sin alpha cdot cos beta +sin beta cdot cos alpha }{cos alpha cdot cos beta } = frac{sin( alpha + beta )}{cos alpha cdot cos beta } \\\tg alpha -tg beta = frac{sin alpha }{cos alpha } - frac{sin beta }{cos beta } = frac{sin alpha cdot cos beta -sin beta cdot cos alpha }{cos alpha cdot cos alpha } = frac{tg( alpha - beta )}{cos alpha cdot cos beta }$