MathTest

A single equation:
<math> \operatorname{erfc}(x) = \frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt = \frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}} </math>	$\operatorname {erfc} (x)={\frac {2}{\sqrt {\pi }}}\int _{x}^{\infty }e^{-t^{2}}\,dt={\frac {e^{-x^{2}}}{x{\sqrt {\pi }}}}\sum _{n=0}^{\infty }(-1)^{n}{\frac {(2n)!}{n!(2x)^{2n}}}$
Multiple-line equation (default alignments):
<math> \begin{align} y &=& x + 2 \\ 5x + 7z &=& 8y^2 + 2y - 5 \end{align} </math>	${\begin{aligned}y&=&x+2\\5x+7z&=&8y^{2}+2y-5\end{aligned}}$
Multiple-line equation (user-set alignments, Right-Center-Left):
<math> \begin{array}{rcl} y & = & x + 2 \\ 5x + 7z &=& 8y^2 + 2y - 5 \end{array} </math>	${\begin{array}{rcl}y&=&x+2\\5x+7z&=&8y^{2}+2y-5\end{array}}$
<math> \chi(\lambda) = \left| \begin{array}{ccc} \lambda - a & -b & -c \\ -d & \lambda - e & -f \\ -g & -h & \lambda - i \end{array} \right| </math>	$\chi (\lambda )=\left|{\begin{array}{ccc}\lambda -a&-b&-c\\-d&\lambda -e&-f\\-g&-h&\lambda -i\end{array}}\right|$