Question

How do you evaluate `sec^-1(1)`?

Answer 1

`sec^-1 1=0`.

Explanation:

By Defn. `sec^-1x=theta, |x|>=1 iff sectheta=x, theta in [0,pi]-{pi/2}`

Since, `sec0=1, where, 0 in [0,pi]-{pi/2}`, we have, `sec^-1 1=0`.