Question

Найдите 3 × tg2a, если tga = 0,5. a - альфа.

Answer 1

Ответ:

$3tg(2 \alpha ) = 3 \times \frac{2tg \alpha }{1 - {tg}^{2} \alpha } = \frac{6tg \alpha }{1 - {tg}^{2} \alpha } = \\ \\ = \frac{6 \times 0.5}{1 - 0.25} = \frac{3}{0.75} = 3 \times \frac{4}{3} = 4$