Which function is represented as sec(x)?

The function sec(x) is defined as the reciprocal of the cosine function. This means that sec(x) = 1/cos(x). The secant function plays a significant role in trigonometry, especially when dealing with angles and right triangles, as it relates to the cosine of an angle.

While other options involve the reciprocals of different trigonometric functions, they do not represent sec(x). For instance, 1/sin(x) defines the cosecant function, 1/tan(x) is the cotangent function, and 1/csc(x) relates to the sine function. Therefore, the option that accurately reflects the definition of the secant function is indeed 1/cos(x).