Latex Added to My Blog!!

Well this is unusal as i just added the $\LaTeX\$ to my Blog!!!

$$\frac{x^n-1}{x-1} = \sum_{k=0}^{n-1}x^k$$

$$x^2$$

$$x^21 \ne x^{21}$$

$$\overline{x+\overline{y}} = \overline{x}+y$$

$$
\left(
\begin{array}{ccc}
a_{11}&\cdots&a_{1n}\\
\vdots&\ddots&\vdots\\
a_{m1}&\cdots&a_{mn}
\end{array}
\right)
$$

$$
\begin{eqnarray*}
1+2+\ldots+n &=& \frac{1}{2}((1+2+\ldots+n)+(n+\ldots+2+1))\\
&=& \frac{1}{2}\underbrace{(n+1)+(n+1)+\ldots+(n+1)}_{\mbox{$n$ copies}}\\
&=& \frac{n(n+1)}{2}\\
\end{eqnarray*}
$$

Enjoy