Question

Знайти tg2x якщо tgx=1/2

Answer 1

$tg2x = \frac{2tgx}{1-tg^2x}$
$tg2x = \frac{2* \frac{1}{2} }{1- \frac{1}{4} } = \frac{1}{ \frac{3}{4} } = \frac{4}{3}$

Answer 2

tg2x=2tgx/(1-tg²x)
tg2x=2*1/2:(1-1/4)=1:3/4=4/3