\log \left(N + 1\right) - \log N
\begin{array}{l}
\mathbf{if}\;N \le 7140.532646773332999146077781915664672852:\\
\;\;\;\;\left(\log \left(\sqrt{\sqrt{\frac{N + 1}{N}}}\right) + \log \left(\sqrt{\sqrt{\frac{N + 1}{N}}}\right)\right) + \log \left(\frac{N + 1}{N}\right) \cdot \frac{1}{2}\\
\mathbf{else}:\\
\;\;\;\;\left(\frac{1}{N} - \frac{0.5}{N \cdot N}\right) + \frac{0.3333333333333333148296162562473909929395}{{N}^{3}}\\
\end{array}double f(double N) {
double r58723 = N;
double r58724 = 1.0;
double r58725 = r58723 + r58724;
double r58726 = log(r58725);
double r58727 = log(r58723);
double r58728 = r58726 - r58727;
return r58728;
}
double f(double N) {
double r58729 = N;
double r58730 = 7140.532646773333;
bool r58731 = r58729 <= r58730;
double r58732 = 1.0;
double r58733 = r58729 + r58732;
double r58734 = r58733 / r58729;
double r58735 = sqrt(r58734);
double r58736 = sqrt(r58735);
double r58737 = log(r58736);
double r58738 = r58737 + r58737;
double r58739 = log(r58734);
double r58740 = 0.5;
double r58741 = r58739 * r58740;
double r58742 = r58738 + r58741;
double r58743 = r58732 / r58729;
double r58744 = 0.5;
double r58745 = r58729 * r58729;
double r58746 = r58744 / r58745;
double r58747 = r58743 - r58746;
double r58748 = 0.3333333333333333;
double r58749 = 3.0;
double r58750 = pow(r58729, r58749);
double r58751 = r58748 / r58750;
double r58752 = r58747 + r58751;
double r58753 = r58731 ? r58742 : r58752;
return r58753;
}



Bits error versus N
Results
if N < 7140.532646773333Initial program 0.1
rmApplied diff-log0.1
rmApplied add-sqr-sqrt0.1
Applied log-prod0.1
rmApplied add-sqr-sqrt0.1
Applied sqrt-prod0.1
Applied log-prod0.1
rmApplied pow10.1
Applied sqrt-pow10.1
Applied log-pow0.1
if 7140.532646773333 < N Initial program 59.6
Taylor expanded around inf 0.0
Simplified0.0
Final simplification0.1
herbie shell --seed 2019305
(FPCore (N)
:name "2log (problem 3.3.6)"
:precision binary64
(- (log (+ N 1)) (log N)))