TeX source:
\begin{array}{rcl}f'_x(x,y) &=& \dfrac{1}{x+y^2}\cdot 1-e^{2xy}\cdot 2y+3\\&=& \dfrac{1}{x+y^2}-2ye^{2xy}+3\\&=& \left(x+y^2\right)^{-1}-2ye^{2xy}+3\end{array}