Question

Resolva as inequações:

a) sen x ≥ - $\frac{1}{2}$
b) cos x < $\frac{ \sqrt{2} }{2}$
c) tg x ≤ - $\frac{ \sqrt{3} }{3}$

Answer 1

a) $\text{sen}~x\ge-\dfrac{1}{2}$

$\text{sen}~210^{\circ}=-0,5$

$\text{sen}~330^{\circ}=-0,5$


$0\le\ x\le\dfrac{7\pi}{6}\cup\dfrac{31\pi}{18}\le x\le2\pi$

b) $\text{cos}~x<\dfrac{\sqrt{2}}{2}$

$\text{cos}~45^{\circ}=\dfrac{\sqrt{2}}{2}$

$\dfrac{\pi}{4}<x<\dfrac{7\pi}{8}$

c) $\text{tg}~x<-\dfrac{\sqrt{3}}{3}$

$\text{tg}~150^{\circ}=-\dfrac{\sqrt{3}}{3}$

$\dfrac{\pi}{2}<x<\dfrac{5\pi}{6}\cup\dfrac{3\pi}{2}<x<\dfrac{11\pi}{12}$