Hi, welcome. See https://tex.stackexchange.com/questions/32140/how-to-write-a-function-piecewise-with-bracket-outside/32142#32142
– Torbjørn T.Mar 11 '18 at 17:55
Thank you, but it didn't give me what I need $u_i=$ $\[ \left\{ \begin{array}{ll} 1 & if OR_i \leq r \\ 0 & if if not\\ \end{array} \right. \]
– azdoudMar 11 '18 at 18:36
Sir @Mico, you mark my question as had an answer, but it did not give me my need
– azdoudMar 11 '18 at 18:39
2
\[ .. \] starts math mode, don't put it inside $ ... $, which also starts math mode. It would likely be better to use the cases environment though. And you'll want to use \text{if } and \text{if not}. For example \documentclass{article} \usepackage{amsmath} \begin{document} \[ u_i= \begin{cases} 1 & \text{if } OR_i \leq r \\ 0 & \text{if not} \end{cases} \] \end{document}
– Torbjørn T.Mar 11 '18 at 18:42
$u_i=$ $\[ \left\{ \begin{array}{ll} 1 & if OR_i \leq r \\ 0 & if if not\\ \end{array} \right. \]– azdoud Mar 11 '18 at 18:36\[ .. \]starts math mode, don't put it inside$ ... $, which also starts math mode. It would likely be better to use thecasesenvironment though. And you'll want to use\text{if }and\text{if not}. For example\documentclass{article} \usepackage{amsmath} \begin{document} \[ u_i= \begin{cases} 1 & \text{if } OR_i \leq r \\ 0 & \text{if not} \end{cases} \] \end{document}– Torbjørn T. Mar 11 '18 at 18:42