E=mc^2$E=mc^2$
\\overbrace{blog.csdn.net/lindexi_gd}_{lindexi} + \\underbrace{lindexi.github.io}_{doubi}$\\overbrace{blog.csdn.net/lindexi_gd}_{lindexi} + \\underbrace{lindexi.github.io}_{doubi}$
\overbrace{1+2+\cdots+100}$\overbrace{1+2+\cdots+100}$
\gamma$\gamma$
\begin{matrix} \sum_{k=1}^N k^2 \end{matrix}$\begin{matrix} \sum_{k=1}^N k^2 \end{matrix}$
katex.render("x=\\frac{-b\\pm\\sqrt{b^2-4ac}}{2a}", document.getElementById("math"));
katex.render("\\sin\\theta \\qquad \\cos\\theta \\qquad \\tan\\theta \\qquad \\cot \\theta", document.getElementById("mathB"));