Question

Isn't arcsec=cos? Since sec=1/cos the inverse of sec would be 1/(1/cos) which would be cos??.

Answer 1

arc secant is not equal to cosine. It can be confusing, because the "-1" exponent (which is used to denote arc secant), could also mean the inverse function of secant. Yes, the inverse function of secant would be cosine. Therefore, the inverse of the inverse of cosine, is simply cosine itself.