Question

solve on the interval 0 2pi

4 sec x+6=-2

Answer 1

A. pi/6, 5pi/6
B. 2pi/3, 4pi/3
C. 7pi/6, 11pi/6
D. pi/3, 5pi/3

Help me please <3 :/

Answer 2

\[4 \sec x+6=-2 \]\[\implies \sec x = -2 = \sec \frac \pi 3 \implies x = 2n \pi \pm \frac \pi 3, n\in \mathbb{W} \]

Can you do from here?

Answer 3

D.?

Answer 4

thanks ;)

Answer 5

it was B

Answer 6

Oops \[\sec x=-2=-\sec ( \frac \pi 3) = \sec (\pi -\frac \pi 3)= \sec \frac {2\pi} 3 \]

now that becomes \[ \implies x = 2n \pi \pm \frac {2\pi} 3, n\in \mathbb{W} \]

Hence B.