If 0°<= 360°, solve the equation, sec x=-2

a. 150° and 210 °
b. 210° and 330°
c. 120° and 240°
d. 240° and 300°

I believe it is C. am i right?

sec (1/cos) is negative in the second and third quadrants. Memorize the sin and cosine curves. C is right.

thought so, thanks!

To solve the equation sec(x) = -2, you can use the inverse of the secant function, which is the cosine function.

First, recall that the secant of an angle is equal to the reciprocal of the cosine of that angle. Therefore, sec(x) = -2 is equivalent to 1/cos(x) = -2.

To find the values of x, you need to find the angles whose cosine is equal to -1/2. In other words, you want to find the angles x for which cos(x) = -1/2.

In the range from 0° to 360°, the angles whose cosine is -1/2 are 120° and 240°.

So, the correct answer is c. 120° and 240°.