The definition in my recompiled pdf is not working like I want

Question

I have a hard time with the definition display. See below, to notice that the Definition A. n supposed to read Definition. An expression... How do I this: "supposed to read Definition. An expression..."? My attempt: I try to fix it with replace 1 in the new a field, but when I recompiled it, the illegal parament of \definition. I tried initially to use the \begin{definition}...\end{definition}. It said \begin{definition} is undefined environment.

Here is the source file:

\documentclass{article}
\usepackage[margin=1in]{geometry} 
\usepackage{amsmath,amsthm,amssymb}
\newcommand{\N}{\mathbb{N}}
\newcommand{\Z}{\mathbb{Z}}
\newcommand{\Q}{\mathbb{Q}}
\newcommand{\R}{\mathbb{R}}
\newcommand{\C}{\mathbb{C}}
\newenvironment{Theorem}[2][Theorem]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Lemma}[2][Lemma]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Reflection}[2][Reflection]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Proposition}[2][Proposition]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Corollary}[2][Corollary]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Definition}[2][Definition]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\title{Videos script- Combining like terms}
\author{Carter Barker}
\date{March 2021}
\begin{document}
\maketitle
\section{Introduction}
In the next couple videos, we will review combining like terms and evaluating expressions, rules of exponents, and expanding and factoring polynomials before getting into solving equations and other algebraic ideas. In this video, we will talk about some basic terminology in mathematics before getting into the main point of the video, combining like terms. So I decided to split this video into two parts. First part is the terminology of expressions. The second part, we will use that terminology to combine like terms as well as evaluating some expressions.

\section{Terminology}
In every field, there are a set of vocabulary for every field, and mathematics is no different. Let's start with what is a mathematical expression:
\begin{Definition}
An expression is a...
\end{Definition}
\end{document}

Why are you trying to reinvent the wheel, instead of using one of the dedicated packages? — Bernard, Mar 15 '21 at 14:11

score 4 · Accepted Answer · answered Mar 15 '21 at 14:17

You are defining definition to have one optional argument and a mandatory one. I guess that you call \begin{theorem}{1} to produce a number, but apparently your definitions don't have a number. With your definition, TeX will grab the first letter in the definition text as the mandatory argument.

Define it with just the optional argument.

\newenvironment{Definition}[1][Definition]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1.}]}{\end{trivlist}}

Full example

\documentclass{article}
\usepackage[margin=1in]{geometry} 
\usepackage{amsmath,amsthm,amssymb}
\newcommand{\N}{\mathbb{N}}
\newcommand{\Z}{\mathbb{Z}}
\newcommand{\Q}{\mathbb{Q}}
\newcommand{\R}{\mathbb{R}}
\newcommand{\C}{\mathbb{C}}
\newenvironment{Theorem}[2][Theorem]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Lemma}[2][Lemma]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Reflection}[2][Reflection]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Proposition}[2][Proposition]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Corollary}[2][Corollary]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{Definition}[1][Definition]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1.}]}{\end{trivlist}}
\title{Videos script- Combining like terms}
\author{Carter Barker}
\date{March 2021}
\begin{document}
\maketitle
\section{Introduction}
In the next couple videos, we will review combining like terms and evaluating expressions, rules of exponents, and expanding and factoring polynomials before getting into solving equations and other algebraic ideas. In this video, we will talk about some basic terminology in mathematics before getting into the main point of the video, combining like terms. So I decided to split this video into two parts. First part is the terminology of expressions. The second part, we will use that terminology to combine like terms as well as evaluating some expressions.

\section{Terminology}
In every field, there are a set of vocabulary for every field, and mathematics is no different. Let's start with what is a mathematical expression:
\begin{Definition}
An expression is a...
\end{Definition}
\begin{Theorem}{1}
A theorem
\end{Theorem}
\end{document}

The definition in my recompiled pdf is not working like I want

1 Answers1