How do I customize equation numbering in IEEEtrantools?

Question

I'm new to LaTeX. I'm using IEEEeqnarrayto align equations in my document (a compilation of solved problems), and I'd like to change equation numbering to (x,y) where x is the question number and y is the equation number (which resets with each question). Also I'd be using this within an enumerate environment, so I'd like the question number x to always match the item number.

If possible, please edit the sample below to make it work as described. I included the packages I'm using in my document to ensure compatibility. Thanks!

\documentclass[notitlepage]{article}
\usepackage{amsmath,amssymb,amsthm,mathrsfs}
\usepackage{IEEEtrantools,nccmath}
\usepackage[margin=1in]{geometry}

\begin{document}

This is a test file for custom equation numbering.
\begin{enumerate}
\item The equations below should be labeled (1.1), unlabeled, and labeled (1.2), in order from top to bottom.
    \begin{IEEEeqnarray}{rCl}
        1+1 & = & 2 \\
        1+2 & = & 3 \nonumber \\
        2+3 & = & 5
    \end{IEEEeqnarray}
\item The equations below should be labeled (2.1), unlabeled, and labeled (2.2), in order from top to bottom.
    \begin{IEEEeqnarray}{rCl}
        3+5  & = & 8 \\
        5+8  & = & 13 \nonumber \\
        8+13 & = & 21
    \end{IEEEeqnarray}
\end{enumerate}

\end{document}

Answer 1

You can use the command \numberwithin from amsmath. This command takes two arguments, both supposed to be counters. Using \numberwithin{<counter1>}{<counter2>} will reset <counter1> every time <counter2> is increased. It will also redefine how a number from <counter1> is displayed, representing it in the form "x.y", where x is the current <counter2> value, and y is the current <counter1> value.

The following example should work for your specific case.

\documentclass[notitlepage]{article}
\usepackage{amsmath,amssymb,amsthm,mathrsfs}
\usepackage{IEEEtrantools,nccmath}
\usepackage[margin=1in]{geometry}

\numberwithin{equation}{enumi}

\begin{document}

This is a test file for custom equation numbering.
\begin{enumerate}
\item The equations below should be labeled (1.1), unlabeled, and labeled (1.2), in order from top to bottom.
    \begin{IEEEeqnarray}{rCl}
        1+1 & = & 2 \\
        1+2 & = & 3 \nonumber \\
        2+3 & = & 5
    \end{IEEEeqnarray}
\item The equations below should be labeled (2.1), unlabeled, and labeled (2.2), in order from top to bottom.
    \begin{IEEEeqnarray}{rCl}
        3+5  & = & 8 \\
        5+8  & = & 13 \nonumber \\
        8+13 & = & 21
    \end{IEEEeqnarray}
\end{enumerate}

\end{document}