TeX Quellcode:

\begin{array}{rcl}g'_y(x,y) &=& \dfrac{7}{10}\cos(x)\cdot(-1)y^{-1-1}+19x\\\\&=& -\dfrac{7}{10}\cos(x)\cdot y^{-2}+19x\\\\&=& -\dfrac{7\cos(x)}{10y^2}+19x\end{array}