Find f′′(x)f''(x)f′′(x) for f(x)=ln(x2+1)f(x) = \ln(x^2+1)f(x)=ln(x2+1).
2−2x2(x2+1)2\frac{2-2x^2}{(x^2+1)^2}(x2+1)22−2x2
2x2+1\frac{2}{x^2+1}x2+12
2x2(x2+1)2\frac{2x^2}{(x^2+1)^2}(x2+1)22x2
−2/(x2+1)2-2/(x^2+1)^2−2/(x2+1)2