\log \left(N + 1\right) - \log N
\begin{array}{l}
\mathbf{if}\;N \le 9550.567671573803:\\
\;\;\;\;\log \left(\frac{1 + N}{N}\right)\\
\mathbf{else}:\\
\;\;\;\;\left(\frac{1}{N} + \frac{\frac{-1}{2}}{N \cdot N}\right) + \frac{\frac{\frac{1}{3}}{N \cdot N}}{N}\\
\end{array}double f(double N) {
double r3570102 = N;
double r3570103 = 1.0;
double r3570104 = r3570102 + r3570103;
double r3570105 = log(r3570104);
double r3570106 = log(r3570102);
double r3570107 = r3570105 - r3570106;
return r3570107;
}
double f(double N) {
double r3570108 = N;
double r3570109 = 9550.567671573803;
bool r3570110 = r3570108 <= r3570109;
double r3570111 = 1.0;
double r3570112 = r3570111 + r3570108;
double r3570113 = r3570112 / r3570108;
double r3570114 = log(r3570113);
double r3570115 = r3570111 / r3570108;
double r3570116 = -0.5;
double r3570117 = r3570108 * r3570108;
double r3570118 = r3570116 / r3570117;
double r3570119 = r3570115 + r3570118;
double r3570120 = 0.3333333333333333;
double r3570121 = r3570120 / r3570117;
double r3570122 = r3570121 / r3570108;
double r3570123 = r3570119 + r3570122;
double r3570124 = r3570110 ? r3570114 : r3570123;
return r3570124;
}



Bits error versus N
Results
if N < 9550.567671573803Initial program 0.1
rmApplied add-log-exp0.1
Simplified0.1
if 9550.567671573803 < N Initial program 59.6
rmApplied add-log-exp59.6
Simplified59.3
rmApplied add-sqr-sqrt59.3
Taylor expanded around inf 0.0
Simplified0.0
Final simplification0.1
herbie shell --seed 2019128
(FPCore (N)
:name "2log (problem 3.3.6)"
(- (log (+ N 1)) (log N)))