\log \left(N + 1\right) - \log N
\begin{array}{l}
\mathbf{if}\;N \le 3318.89906958905294:\\
\;\;\;\;\left(\sqrt[3]{\log \left(N + 1\right)} \cdot \sqrt[3]{\log \left(N + 1\right)}\right) \cdot \sqrt[3]{\log \left(N + 1\right)} - \log N\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(\frac{1}{{N}^{2}} \cdot \left(\frac{0.333333333333333315}{N} \cdot \frac{0.333333333333333315}{N} - 0.5 \cdot 0.5\right)\right) \cdot N + \left(\frac{0.333333333333333315}{N} + 0.5\right) \cdot 1}{\left(\frac{0.333333333333333315}{N} + 0.5\right) \cdot N}\\
\end{array}double f(double N) {
double r43255 = N;
double r43256 = 1.0;
double r43257 = r43255 + r43256;
double r43258 = log(r43257);
double r43259 = log(r43255);
double r43260 = r43258 - r43259;
return r43260;
}
double f(double N) {
double r43261 = N;
double r43262 = 3318.899069589053;
bool r43263 = r43261 <= r43262;
double r43264 = 1.0;
double r43265 = r43261 + r43264;
double r43266 = log(r43265);
double r43267 = cbrt(r43266);
double r43268 = r43267 * r43267;
double r43269 = r43268 * r43267;
double r43270 = log(r43261);
double r43271 = r43269 - r43270;
double r43272 = 1.0;
double r43273 = 2.0;
double r43274 = pow(r43261, r43273);
double r43275 = r43272 / r43274;
double r43276 = 0.3333333333333333;
double r43277 = r43276 / r43261;
double r43278 = r43277 * r43277;
double r43279 = 0.5;
double r43280 = r43279 * r43279;
double r43281 = r43278 - r43280;
double r43282 = r43275 * r43281;
double r43283 = r43282 * r43261;
double r43284 = r43277 + r43279;
double r43285 = r43284 * r43264;
double r43286 = r43283 + r43285;
double r43287 = r43284 * r43261;
double r43288 = r43286 / r43287;
double r43289 = r43263 ? r43271 : r43288;
return r43289;
}



Bits error versus N
Results
if N < 3318.899069589053Initial program 0.1
rmApplied add-cube-cbrt0.1
if 3318.899069589053 < N Initial program 59.3
Taylor expanded around inf 0.1
Simplified0.1
rmApplied flip--0.1
Applied associate-*r/0.1
Applied frac-add0.1
Final simplification0.1
herbie shell --seed 2020083
(FPCore (N)
:name "2log (problem 3.3.6)"
:precision binary64
(- (log (+ N 1)) (log N)))