> For the complete documentation index, see [llms.txt](https://overleaf-pro.ayaka.space/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://overleaf-pro.ayaka.space/latex/zh-cn/latex-cuo-wu/02-command-r-invalid-in-math-mode-on-input-line-xxx.md).

# 在数学模式中，命令 \r 在输入行 XXX 无效

当在数学模式中错误使用特殊字符时会出现此错误。在 LaTeX 中，某些字符，如带重音符号的字母或带变音符号的字母，不能在数学模式中书写。解决此问题的最佳方法是将它们写在 **`\text{...}`** 由该 **`amsmath`** 宏包。

## 常见原因

**在数学模式中包含带重音符号、变音符号等的字母：**

例如，ö 实际上是 {\\"o}

**在数学模式中使用特殊符号：**

例如，angstrom \AA 实际上是 \r{A}


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