Question

qual o valor de cos (-2π/3) e cos (-7 pi)?

Answer 1

Oie, Td Bom?!

I.

$= \cos( - \frac{2\pi}{3} )$

$= \cos( \frac{2\pi}{3} )$

$= - \frac{1}{2}$

II.

$= \cos( - 7\pi)$

$= \cos(7\pi)$

$= \cos(\pi \: . \: 2 \: . \: 3\pi )$

$= \cos(\pi)$

$= - 1$

Att. Makaveli1996