Question

Qual o valor de sen 150° + cos 120°? * 4 pontos a) 0 b) 1 c) -1 d) 1/2

Answer 1

Resposta:

a) 0

Explicação passo a passo:

$\sin \left(150^{\circ \:}\right)+\cos \left(120^{\circ \:}\right)$

$=\cos \left(90^{\circ \:}-150^{\circ \:}\right)+\cos \left(120^{\circ \:}\right)$

$=\cos \left(-60^{\circ \:}\right)+\cos \left(120^{\circ \:}\right)$

$=\cos \left(60^{\circ \:}\right)+\cos \left(120^{\circ \:}\right)$

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

$=0$