Question

Tg альфа =1\2. tg 2 альфа=?

Answer 1

$tg2 \alpha = \frac{2tg \alpha }{1- tg^{2}}= \frac{2* \frac{1}{2} }{1- (\frac{1}{2})^{2}} = \frac{1}{1- \frac{1}{4}}= \frac{1}{ \frac{3}{4}}= \frac{3}{4}$