Latex Undefined control sequence. ...\bm

遇到Undefined control sequence問題

原來是\bm{\theta}無法識別

解決方法:

To use \boldsymbol (in math mode, of course), you need to load the amsmath package.

Alternatively, load the bm ("bold math") package and write \bm{\beta} (again in math mode, of course).

e,g,

    \documentclass{article}
    \usepackage{amsmath} % for \boldsymbol macro
    \usepackage{bm}      % for \bm macro
    \begin{document}
    $\boldsymbol{\beta} = (\beta_1,\beta_2,\dots,\beta_n)$
     
    $\bm{\beta} = (\beta_1,\beta_2,\dots,\beta_n)$
    \end{document}

轉載於:https://www.cnblogs.com/Lisamon/p/11141553.html