How do you make a big Laplace Transform symbol

Question

\documentclass{article}
\usepackage[hmargin=1in,vmargin=1in]{geometry}
\usepackage{amsmath,cancel,color,mathrsfs}
\begin{document}
Derivation of $ \mathscr {L} \{\int_0^{t} f(\tau)\,d\tau\} $

\end{document}

So far this is what I have but I'd like to use \displaystyle for the integral to make it look nicer since the top and bottom limits are kinda squished, but then the Laplace part is too small and I have no idea how to make it bigger

Any help is appreciated

Answer 1

You could load the relsize package and use the \mathlarger macro (once or repeatedly) to enlarge \mathscr{L}. In the third row of the following screenshot, the enlarged \mathscr{L} is generated by two calls to \mathlarger; don't overdo the enlarging stuff.

\documentclass{article}
\usepackage{mathrsfs,relsize,array}
\newcommand\Laplace{\mathlarger{\mathlarger{\mathscr{L}}}}
\begin{document}

$\begin{array}{>{$}l<{$} c}
original form & 
\mathscr {L} \{\int_0^{t} f(\tau)\,d\tau\} \\[2ex]
displaystyle & 
\mathscr{L} \biggl\{\displaystyle\int_0^{t} \! f(\tau)\,d\tau\biggr\} \\[4ex]
enlarged $\mathscr{L}$, displaystyle & 
\Laplace \biggl\{\displaystyle\int_0^{t} \! f(\tau)\,d\tau\biggr\} \\
\end{array}$

\end{document}