0

Beginner here, I have been trying to use Overleaf after writing on ShareLaTex but the text isn't being correctly read. This is the original code:

\left\{
\begin{array}{11}
  \frac{x^2+2x}{x+1} \geq 0 \\
  x > -1 \\
\end{array} 
\right.

And this is the error I get:

LaTeX Error: Illegal character in array arg.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
...                                              

l.43 \begin{array}{11}

What did I do wrong?

  • 5
    Welcome to TeX.SE! It's ll, not 11. l, as in left-align. – Troy Dec 11 '17 at 16:18
1

Your code works in the following way (see Troy's comment)

\documentclass{article}
 \begin{document}
\[
\left\{
\begin{array}{l} % not \begin{array}{11}
  \frac{x^2+2x}{x+1} \geq 0 \\
  x > -1 \\
\end{array} 
\right.
\]
\end{document}

but it is better:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\left\{
\begin{aligned}
  \frac{x^2+2x}{x+1} &\geq 0 \\
  x &> -1 \\
\end{aligned} 
\right.
\]
\end{document}

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.