# Memoir Extra Font Size Math running off of page

I'm using the memoir class with extrafontsizes to try and enlarge some math notes. However, when I use the following preamble:

\documentclass[letterpaper,48pt,extrafontsizes]{memoir}


Things are running off the page like so:

Has anyone modified the class to correct for this?

Small reproducible code for the screenshot

\documentclass[letterpaper,48pt,extrafontsizes]{memoir}
\usepackage{amsmath}
\begin{document}
with
\begin{aligned} E_1(h,k)&=\frac{1}{2}\left[-h^2\left(y+\theta k\right)^2\cos\left((x+\theta h)(y+\theta k)\right)\right.\\ &-k^2\left(x+\theta h\right)^2\cos\left((x+\theta h)(y+\theta k)\right)\\ &\left.-2hk\left[\left(x+\theta h\right)(y+\theta k)\cos\left((x+\theta h)(y+\theta k)\right)+\sin\left((x+\theta h)(y+\theta k)\right)\right]\right] \end{aligned}
\end{document}

• corrected @DavidCarlisle Aug 28 '18 at 18:38

With such large font I would give up on alignment as you really can't afford the space it takes up. Here with multline* it is still ~40pt too wide but at least fits on the physical page.

As all math line breaking is manual, there is no "fix" needed in the class, it is the document author's responsibility to make it fit.

\documentclass[letterpaper,48pt,extrafontsizes]{memoir}
\usepackage{amsmath}
\begin{document}
with
\begin{multline*}
E_1(h,k)=\frac{1}{2}[-h^2(y+\theta k)^2\\