Is there a way to make only a part of an equation larger? I'm working with the code below, but I feel like the s-angle-n and a-angle-n are far too small and would really like to make them both bigger without affecting the rest of the equation.
\DeclareRobustCommand{\lcroof}[1]{
\hbox{\vtop{\vbox{%
\hrule\kern 1pt\hbox{%
$\scriptstyle #1$%
\kern 1pt}}\kern1pt}%
\vrule\kern1pt}}
\DeclareRobustCommand{\angle}[1]{
_{\lcroof{#1}}}
\begin{align*}
s\angle{n}&=\dfrac{(1+r)^n-1}{r}\\
a\angle{n}&=\dfrac{1-\dfrac{1}{(1+r)^n}}{r}
\end{align*}
Thanks for any help.