Secant, cosecant and cotangent, almost always written as sec, cosec and cot are trigonometric functions like sin, cos and tan. Note, sec x is not the same as cos-1x (sometimes written as arccos x).
Similarly, is arc cosine the same as inverse cosine?
Note: arccos refers to "arc cosine", or the radian measure of the arc on a circle corresponding to a given value of cosine. Technical note: Since none of the six trig functions sine, cosine, tangent, cosecant, secant, and cotangent are one-to-one, their inverses are not functions.
What is the inverse of the cosine?
Specifically, they are the inverses of the sine, cosine, tangent, cotangent, secant, and cosecant functions, and are used to obtain an angle from any of the angle's trigonometric ratios. Inverse trigonometric functions are widely used in engineering, navigation, physics, and geometry.