What is is arccos the same as sec?

No, arccos is not the same as sec (secant). They are different trigonometric functions with distinct meanings and functionalities.

• Arccos (also written as cos⁻¹) is the inverse of the cosine function. It answers the question: "What angle has a cosine of x?". Its domain is [-1, 1], and its range is [0, π] (in radians) or [0°, 180°] (in degrees).

• Secant (sec) is the reciprocal of the cosine function. That is, sec(x) = 1 / cos(x). Its domain is all real numbers except for odd multiples of π/2, and its range is (-∞, -1] ∪ [1, ∞).

In summary, arccos is an inverse function that returns an angle, while secant is a reciprocal function that returns a ratio. They are related through the cosine function, but they perform different operations and have different inputs and outputs.