I have a function, $f(x) = \sec x + \csc x$ on the interval $x \in (0, \pi/2)$.
The derivative of it is, $f'(x) = \csc^2(x) \sec^2(x) \left(\sin^3 x + \cos^3 x\right)$
Of course, when I tried to solve for $f'(x) = 0$, I realize that $f'(x)=0$ does not exist.
However, the question insists that the there is a minimum. Am I doing something wrong here?