How to make math symbols bigger?

Question

Is there a way to make math symbols bigger?

Reason: I've used \sfrac{q}{m}, and those symbols appear far to small, so I would like to make them a bit bigger.

edit: I just thought that \sfrac{q}{m} should look nicer if it is bigger when it is followed by =.

edit 2: Context:

some text
\[
  \dfrac{q}{m} \propto \frac{4\pi{r^2}}{\frac{4}{3}\pi{r^3}}\
  \propto 3{r^\alpha}\text{, \quad gdje je\quad}\;\alpha = -1 \text{.}
\]
some text

Answer 1

Another possibility are the \mathlarger and \mathsmaller commands provided by the relsize package.

These can be iterated to make bigger and bigger

 \documentclass{article}
 \usepackage{relsize}
 \begin{document}
 \[
    x+y=z \leftrightarrow \mathlarger{\mathlarger{\mathlarger{(x+y=z)}}}
 \]
 \end{document}

It doesn't always work well with large operators, though.

Answer 2

It is really advisable to always provide a minimal example. The easiest way to scale it (you essentially scaling the font) is to use the \scalebox macro from the graphicx package as follows:

\documentclass{article}
\usepackage{graphicx}
\usepackage{xfrac}
\begin{document}
 Scale at 1.5 times  \scalebox{1.5}{\sfrac{3}{2}}

 This is much larger  \scalebox{3}{\sfrac{3}{2}}
\end{document}

You can place the whole thing in a new macro if you wish:

\newcommand\scaledfrac[2]{\scalebox{2}{\sfrac{#1}{#2}}}

\scaledfrac{3}{2}

Answer 3

This is an answer to the version of edit 2 that I just produced myself ...

As your math formula is in display style, you can just use \frac{q}{m}; this will give you a large fraction. It's also OK to use \dfrac{q}{m}; this will yield the same result: \dfrac just puts a fraction in display style.