Math & Science ⇒ Error When writing this equation

[jack666sparrow]

Hi

My code

Code: Select all

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage[a4paper,body={},top=1.5cm, left=2.5cm,right=1cm,bottom=2.5cm,nohead]{geometry}


%===============  Begin Document ==================

\begin{document}
\begin{enumerate}
   \item Question \#1\\  
   {\bf Answer.}
2-2.7+2.7^2-...+2(-7)^n=$\frac{1-(-7)^n+1}{4}
   
\end{enumerate}

\end{document}

It says the error in this line

Code: Select all

2-2.7+2.7^2-...+2(-7)^n=$\frac{1-(-7)^n+1}{4}

How can I fix it ?

[Johannes_B]

You only have one single Dollar-sign, but you need two to enclose math (it's the same with braces, parenthesis and brackets).

Code: Select all

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage[a4paper,body={},top=1.5cm, left=2.5cm,right=1cm,bottom=2.5cm,nohead]{geometry}

\begin{document}
\begin{enumerate}
	\item Question \#1\\  
		{\bf Answer.}
$2-2.7+2.7^2-...+2(-7)^n=\frac{1-(-7)^n+1}{4}$
\end{enumerate}
\end{document}

Are you aware that there are multiple classes and packages providing Q/A-things? I even showed a simple hand made approach here once.

[jack666sparrow]

Thanks a lot bro