Determine the open intervals on which the graph is concave upward or concave downward. (Enter your answers using interval notation. If an answer does not exist, enter DNE.) f(x)=(x^2 +8)/(x^2 -1)

Question

I've gotten to the 2nd derivative, but I'm confused about where to go from there. Any help would be rad! Cheers!

Answer 1

First calculate df/dx and find the critical point(s) df/dx=0 the calculate d²f/dx² and evaluate at the critical point if it' <0 then f(x) is concave down. f(x) is concave down (-1,1)

Jim