- TeX source:
- \begin{array}{rcl} f'_x(x,y,z) &=& \dfrac{\pi\sin\left(7y^5\right) \cdot e^{10xz+1} - \pi x\sin\left(7y^5\right) \cdot e^{10xz+1}\cdot 10z}{\left(e^{10xz+1}\right)^2} \cr \cr &=& \dfrac{\left(\pi-10\pi xz\right) \sin\left(7y^5\right) e^{10xz+1}}{\left(e^{10xz+1}\right)^2} \cr \cr&=& \dfrac{\left(\pi-10\pi xz\right) \sin\left(7y^5\right)}{e^{10xz+1}}\end{array}