Question

Solve on the interval [0,2pi):

4 sec x + 6 = -2
A. 2pi/3,4pi/3
B. pi/6,5pi/6
C. pi/3,5pi/3
D. 7pi/6,11pi/6

Answer 1

@RaphaelFilgueiras Why?

Answer 2

cos(x)=-1/2

Answer 3

sorry i forget minus

Answer 4

\[4 \sec x + 6 = -2\]\[4 \sec x = -8\]\[\sec x = -2\]\[\frac{1}{\cos x} = -2\]\[\cos x = - \frac{1}{2}\]\[x = \frac{2 \pi}{3}, \frac{4 \pi}{3}\]

Answer 5

pi-pi/3,pi+pi/3