# How to make everything bold in math mode? [duplicate]

I want to write everything in math mode as bold characters. I know that with bm package I can do that. Here is my example code.

\documentclass{article}
\usepackage{bm,amsmath}

\begin{document}
$E = \frac{1}{2} mv^2$. \newline
$$E =mc^2$$
\begin{align}
\tan x = \frac{\sin x}{\cos x}
\end{align}

\hrule
% I don't want to use \bm{} everytime.
$\bm{E = \frac{1}{2} mv^2}$. \newline
$$\bm{E =mc^2}$$
\begin{align}
\bm{\tan x = \frac{\sin x}{\cos x}}
\end{align}

\end{document}


I don't want to write \bm{} for every mathematical expression. I want bold characters whenever I write any mathematical expression inside  or $$...$$. Is there any way around?