Quotientregel

\( \eqalign{ & \left[ {\frac{t} {n}} \right]' = \cr & \left[ {t \cdot n^{ - 1} } \right]' = \cr & t' \cdot n^{ - 1} + t \cdot - 1 \cdot n^{ - 2} \cdot n' = \cr & \frac{{t'}} {n} - \frac{{t \cdot n'}} {{n^2 }} = \cr & \frac{{t' \cdot n}} {{n^2 }} - \frac{{t \cdot n'}} {{n^2 }} = \cr & \frac{{t' \cdot n - t \cdot n'}} {{n^2 }} \cr} \)