Question

on what intervals ln(x^2+4) concave up?

Answer 1

I think its concave up for all real x

Answer 2

thats not the answer apparently :(
i thought so too

Answer 3

f(x)=ln(x^2+4)
f'(x)= 2x/(x^2+4)
f''(x) = - 2(x^2 -4)/ (x^2 +4)^2
f(x) concave up when f''(x)>0
f(x) concave up for -2<x<2