# Reference from a different folder

I'm writing my thesis and have trouble reference labels between chapters. My main folder look like this:

• Main Folder, where I have the main tex file and folders where I have the main tex file and folders

1. main tex file, where the documentclass, userpackage, etc are located. With the \makechapter{The First Chapter} \input{Chapter1/chapter1.tex}
\makechapter{The Second Chapter} \input{Chapter2/chapter2.tex}
2. Chapter1 (Folder, where inside the file i write in)
chapter1.tex
3. Chapter2 (Folder, where inside the file i write in)
chapter2.tex

When I write in chapter1.tex

\section(Chapter One) \label(Ch1)
$$\label{eq:1} a^2 + b^2 = c^2$$


How can I in chapter2.tex file, reference the labels in chapter1, which is located in a file located in another folder?, for example when I write in chapter2.tex,
As equation \lable(eq:1) in chapter \lable(Ch1) show.

Because now it just shows [??]

Technically, this should work (if not, post your MWE). See the following MWE.

main.tex

   documentclass[12pt,a4paper]{book}

\begin{document}

\input{ch1/ch1.tex}
\input{ch2/ch2.tex}

\end{document}


now, ch1.tex

\chapter{ch1}
$$\label{eq:1} x= x \,$$


and ch2.tex

\chapter{ch2}
$$\label{eq:2} x= x \,$$

Eq.~\ref{eq:1} ...


produces, following ---