MathJax Samples
\left(\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right)\left\lbrace\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right\rbrace\left[\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right]\left\lceil\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right\rceil\left\lfloor\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right\rfloor\left\lgroup\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right\rgroup\left\lmoustache\frac{\frac{\sum_x^y}{\sum_x^y}}{\frac{\sum_x^y}{\sum_x^y}}\right\rmoustache \Biggl(
\[
\left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)
\]
\[
\mathbf{V}_1 \times \mathbf{V}_2 = \begin{vmatrix}
\mathbf{i} & \mathbf{j} & \mathbf{k} \\
\frac{\partial X}{\partial u} & \frac{\partial Y}{\partial u} & 0 \\
\frac{\partial X}{\partial v} & \frac{\partial Y}{\partial v} & 0
\end{vmatrix}
\]
\[
P(E) = {n \choose k} p^k (1-p)^{ n-k}
\]
\[
1 + \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots =
\prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})},
\quad\quad \text{for $|q|<1$}.
\]
\[
\frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} =
1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}}
{1+\frac{e^{-8\pi}} {1+\ldots} } } }
\]
\[
\begin{aligned}
\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \\ \nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0 \end{aligned}
\]
Finally, while display equations look good for a page of samples, the ability
to mix math and text in a paragraph is also important.
This expression \[\sqrt{3x-1}+(1+x)^2\]
is an example of an inline equation. As you see, MathJax equations
can be used this way as well, without unduly disturbing the spacing between lines.