I have the following line: $0 \leqslant b \leqslant 1$
I want to display 0 <= b <= 1, but I get Undefined control sequence
thanks
[Tex/LaTex] \leqslant causes “Undefined control sequence”
math-modesymbols
Related Solutions
Neither \/ nor \? are control sequences in LaTeX*, causing the error. Instead, you're probably looking for:
\documentclass{article}
\begin{document}
\begin{description}
\item [\texttt{/} or \texttt{?}] - Search for a pattern of text, jump to it by hitting Enter
\end{description}
\end{document}
The above minimal example typesets / and ? in a monospaced Computer Modern (or typewriter-style) font, within the description environment's \item. Not sure what exactly your context is, but if you want to include the square brackets [...], use
\item [{[\texttt{/} or \texttt{?}]}] ...
instead. This puts the contents of the \item's optional argument in a group, rather than confusing TeX in using unmatched brackets and causing spacing problems:
* Well, \/ is a control sequence (using as an italic correction), but not the one you're after...
Load the amsfonts package, this provides that command:
\documentclass{article}
\usepackage{amsfonts}
\begin{document}
$\mathbb{Z}$
\end{document}
Optionally you could load amssymb, as this in turn loads amsfonts.
\documentclass{article}
\usepackage{amssymb}
\begin{document}
$\mathbb{Z}$
\end{document}
For reference, the Comprehensive LaTeX Symbol List has also a table of mathematical alphabets, and the packages required for using them. In the current version (dated 25 June 2020) of the document, it is table 316 with the caption Math Alphabets. It is the final table in chapter 3 Mathematical symbols.
Best Answer
do you want it like this way?
$0 \le b \le 1$. Otherwise load\usepackage{amssymb}