Question

How do you evaluate `sec^-1(sec(-(pi)/10))`?

Answer 1

`pi/10`

Explanation:

Given a function `f(x)` and its inverse `f^-1(x)`

Then `f^-1(f(x)) = x`

`:. sec^-1(sec(-pi/10)) = abs(pi/10)`

However, since the range of `sec^(-1) (x)` is `[0,pi/2) uu (pi/2,pi]`

`x=pi/10`