Question

Which of the following represents the domain and range of y = sec x?

Answer 1

First choice

Explanation:

The domain is between -infinity and infinity, and if you use a unit circle, you can find that it is undefined at angles of 90 and 270, so it is pi/2 + n*pi if you use radians. Using a unit circle, the range for cos (x) is [-1, 1], so the range of sec (x) or 1/(cos(x)) is (-inf, -1] U [1, inf) or y <= -1 or y >= 1, so the answer is the first choice.