Wieso gilt die Beziehung?
\( \frac{f^{\prime}(x)}{f(x)}=\frac{1}{x+1}-1 \quad(f(x) \neq 0) \)
\( \begin{array}{ll}\frac{x^{\prime}(t)}{f(t)} d t=\int \limits_{x}^{x}\left(\frac{1}{t+1}-1\right) i t & (a \in I D) \\ \ln |f(x)|=\ln |x+1|-x+c & & (c \in \mathbb{R})\end{array} \)
Also warum ist das: Integral von f ' / f = ln (f(x)