Question

Se tgα=1/3,então tg 2α é:
a)1/3 b)2/3 c)3/8 d)3/4

Answer 1

tg 2α = 2.tgα / (1 - tgα²)
tg 2α = 2.(1/3) / (1 - (1/3)²)
tg 2α = 2/3 / (1 - 1/9)
tg 2α = 2/3 / (8/9)
tg 2α = 2/3 . 9/8
tg 2α = 18/24
tg 2α = 3/4

Resposta: letra "d"