Curve sketching for f(x)= (x^2 - 8)/(x^2 - 4)

[cmnalo]

I eventually need to sketch the graph. But first I need help finding the intervals where the function is increasing and decreasing. So, I need to find the 1st deriviative. I'm not sure it my finding so far is correct? I would apprecite it if someone could help me with this first step. After I get the correct 1st. derivative I plan on making a Sign chart for f'.

function: f(x)= (x^2 - 8)/(x^2 - 4)

my derivative: f'(x) = 8 / (x^2 - 4)^2

 

[skeeter]

\(\displaystyle \L f'(x) = \frac{8x}{(x^2-4)^2}\)

 

[cmnalo]

Would it be correct to say that the horizontal asymtote is + or- 2?
When I try to do a sign chart things don't seem to match the answer. Any suggestions on my next step for sketching this curve?