Verified answer

Ответ:

[tex] \tg(2 \alpha ) = \frac{2 \tg( \alpha ) }{1 - \tg^{2} ( \alpha ) } [/tex]

[tex] \tg(2 \alpha ) = \frac{2 \times \frac{1}{2} }{1 \times \frac{1}{4} } = \frac{1}{ \frac{3}{4} } = \frac{4}{3} [/tex]

[tex] \tg(2 \alpha ) = \frac{4}{3} = 1 \frac{1}{3} [/tex]