Find the derivative of f(x)=ln(x2+1+x)f(x) = \ln(\sqrt{x^2+1} + x)f(x)=ln(x2+1+x).
1x2+1\frac{1}{\sqrt{x^2+1}}x2+11
1x2+1\frac{1}{x^2+1}x2+11
xx2+1\frac{x}{\sqrt{x^2+1}}x2+1x
111