如何在rmarkdown编织的数学模式下将粗体希腊字母写到html?

How to write bold greek letters in math mode of rmarkdown knitting to html?

如何在rmarkdown编织的数学模式下将粗体希腊字母写到html?我试过了

---
title: "try bold greek"
author: "test"
date: "6/17/2021"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)

\usepackage{bm}

测试

测试 1: $\mathbf{\alpha}$

测试 2: $\bm{\alpha}$

测试 3: $\alpha$

which renders no bold fonts at all:
"
Test 1: α

Test 2: \bmα

Test 3: α
"

这应该有效:

$\boldsymbol{\alpha}$