Henrik S. answered 01/04/15
Tutor
5
(9)
Patient Math Tutor from 1995 till now.
Second derivative of the function is f"(x)=-6(x+1)^-4 ,which is negative on both (-inf,-1)and(-1,inf),
So the function is concave down on each of intervals.
So the function is concave down on each of intervals.