TeX Quellcode:

\begin{array}{rcl}f'_t(t,z) &=& \dfrac{1}{1+t}\cdot 1\cdot z^2+5\cdot 2t^{2-1}z-0\\&=& \dfrac{z^2}{1+t}+10tz\\&=& z^2\cdot \left(1+t\right)^{-1}+10tz\end{array}