[Math] Add shortcut for writing partial derivatives

main/math.tex

@@ -28,6 +28,8 @@
 \newcommand{\defAs}{\overset{\text{def}}{=}}
 \newcommand{\der}[1]{\frac{\mbox{d}}{\mbox{d}#1}}
 \newcommand{\dern}[2]{\frac{\mbox{d}^{#2}}{\mbox{d}^{#2}#1}}
+\newcommand{\parder}[1]{\frac{\partial}{\partial #1}}
+\newcommand{\pardern}[2]{\frac{\partial^{#2}}{\partial^{#2} #1}}
 \newcommand{\defEquiv}{\overset{\text{def}}{\Leftrightarrow}}
 \newcommand{\defImplies}{\overset{\text{def}}{\Rightarrow}}
 \newcommand{\divides}{\hspace{0.25em}|\hspace{0.25em}}