I believe I found the answer to part a), and I also think I could find part c).

I just don't know how to evaluate part b). I was thinking of using the squeeze theorem (or whatever you'd like to call it), but I don't know...

$\displaystyle {-\pi \over 2} \leq tan^-1({-16 \over x-2}) \leq {\pi \over 2}$

I don't really know what to do with this