Question

tg альфа =12. tg 2 альфа=?

Answer 1

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