Using the chain rule:
d/dx (ln(sqrt(x^2+1))) = 1/sqrt(x^2+1) d/dx sqrt(x^2+1)ddx(ln(√x2+1))=1√x2+1ddx√x2+1
d/dx (ln(sqrt(x^2+1))) = 1/sqrt(x^2+1) 1/(2sqrt(x^2+1))d/dx (x^2+1)ddx(ln(√x2+1))=1√x2+112√x2+1ddx(x2+1)
d/dx (ln(sqrt(x^2+1))) = 1/(2(x^2+1))(2x)ddx(ln(√x2+1))=12(x2+1)(2x)
d/dx (ln(sqrt(x^2+1))) = x/(x^2+1)ddx(ln(√x2+1))=xx2+1
We can also note that using the properties of logarithms:
(ln(sqrt(x^2+1))) = 1/2 ln(x^2+1)(ln(√x2+1))=12ln(x2+1)
and simplify the passages:
d/dx (ln(sqrt(x^2+1))) = 1/2 d/dx ln(x^2+1) = 1/2 1/(x^2+1) d/dx (x^2+1) = (1/2)( 1/(x^2+1) )(2x )= x/(x^2+1)ddx(ln(√x2+1))=12ddxln(x2+1)=121x2+1ddx(x2+1)=(12)(1x2+1)(2x)=xx2+1