Question

Sendo a + b = 45° e tg a = 5 , calcule tg b .

A) -2/3
B) 2/3
C) 3/2

D) -3/2
E) O

Answer 1

Resposta:

A

Explicação passo-a-passo:

$tg(a+b) = \frac{tga+tgb}{1-tga.tgb}$

$tg45 = \frac{5+tgb}{1- 5.tgb}$

$1=\frac{5+tgb}{1-5tgb}$

1 - 5tgb = 5 + tgb

1 - 5 = tgb + 5tgb

-4 = 6tgb

-4/6 = tgb

tgb = -2/3