I want to change the font size to 13pt in LaTeX, while using the Times font family (with mathptmx). However, I always get the error message "Unused global option(s):", referring to the font size of "13pt" specified in the documentclass options (see example below).
How can I set the font size to 13pt throughout the whole document after using "mathptmx"?
I couldn't find any solution by doing extensive research on the internet.
\documentclass[13pt]{article}
\usepackage{lipsum}
\usepackage[utf8]{inputenc}
\usepackage[a4paper, lmargin={2cm},rmargin={2cm},tmargin={2cm},bmargin={2cm}]{geometry}
\usepackage{mathptmx}
\begin{document}
\lipsum[1-5]
\end{document}