ngaje

\Huge$\Frac{a}{b}$

(\Huge$\Frac{a}{b}$)

Mathmode

$
\begin{equation}
x = a_0 + \frac{1}{\displaystyle a_1
  + \frac{1}{\displaystyle a_2
  + \frac{1}{\displaystyle a_3 + a_4}}}
\end{equation}
$

$
\begin{equation}
x = a_0 + \frac{1}{\displaystyle a_1
  + \frac{1}{\displaystyle a_2
  + \frac{1}{\displaystyle a_3 + a_4}}}
\end{equation}
$

$
\
x = a_0 + \frac{1}{\displaystyle a_1
  + \frac{1}{\displaystyle a_2
  + \frac{1}{\displaystyle a_3 + a_4}}}
\
$$

[[$x^2+y^2=z^2$]]

[[$\mbox{\fontsize{12}{14}\selectfont $x^2+y^2=z^2$}$]]

[[$\mbox{\fontsize{14}{17}\selectfont $x^2+y^2=z^2$}$]]

[[$\mbox{\fontsize{17}{20}\selectfont $x^2+y^2=z^2$}$]]

[[$\mbox{\fontsize{20}{24}\selectfont $x^2+y^2=z^2$}$]]

[[$\mbox{\fontsize{24}{30}\selectfont $x^2+y^2=z^2$}$]]

http://community.wikidot.com/forum/t-5373/how-to-change-the-size-of-formulas

$\DeclareMathSizes{13.82}{14.4}{10}{7}$