TeX source:
\begin{array}{rcl}f'_z(x,y,z) &=& \dfrac{3}{2}\cdot 3x^2y^{\frac{1}{2}}z^{3-1}+0\\\\&=& \dfrac{9}{2}x^2y^{\frac{1}{2}}z^2\\\\&=& \dfrac{9}{2}x^2\sqrt{y}z^2\end{array}