Evaluate each of the following:

(i)`sec^(-1)(secpi/3)`

(ii) `sec^(-1)(sec(2pi)/3)`

(iii) `sec^(-1)(sec(5pi)/4)`

Explanation

(i)
We know that
$$ \sec ^{-1}(\sec \theta)=\theta, \quad[0, \pi / 2) \cup(\pi / 2, \pi] $$
We have
$$
\sec ^{-1}\left(\sec \frac{\pi}{3}\right)=\frac{\pi}{3}
...