Question

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

Answer 1

A fundamental property of all inverses is:

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

Explanation:

Applying the above property:

`tan^-1(tan(x)) = x`

Substitute `x = -pi/10`:

`tan^-1(tan(-pi/10)) = -pi/10`