Text Formatting ⇒ Symbol Command causes Error

[sachinrajsharma]

Hi,

I'm using the following source code for making a case differentiation. However, it is showing in the log "undefined control sequence". Please help, where I am wrong in coding.

Code: Select all

\documentclass[10pt,a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}

\begin{document}
  $$
    f(x) = 
    \begin{cases}
      |2x-3|[x] & \text{if} \ x\ge1 \\ 
      \sin\frac{\pi x}{2} & \text{if} \ x\lt 1 \ 
    \end{cases}.
  $$
\end{document}

Regards,

Sachin

[cgnieder]

Simply replace \lt by <.

By the way: $$ ... $$ is plain TeX syntax and should be avoided in a LaTeX document, see Why is \[ … \] preferable to $$ … $$? for reasons why.

Regards

[sachinrajsharma]

Thanks a lot... thanks once again it fine now....

Sachin Sharma